Building a 100% virtual SNA network on your desk!

So I have been fighting the Mainframe thing for a while (see part1/part2) and getting nowhere. I couldn’t shake the feeling that it was working, but something on the mainframe side was broken. I just don’t know enough about MVS/VTAM on the host side. Although I have setup and deployed quite a few cisco routers in production doing remote ring groups, translational bridges, and the like, a DLSw connection to SDLC was something I’d never done as I’d always had direct token-ring access to the FrontEndProcessor.

On suspicion that I’ve been talking to the mainframe the whole time is that in the packet trace from Microsoft SNA server I’d see the string UNSUPPORTED FUNCTION in the capture.

Microsoft SNA Server

The LU goes online, but there just isn’t anything to be displayed. Traffic is constantly flowing but it’s always the same, a blank dead screen.

On a fluke I had spotted a copy of Attachmate Extra! 4.20 on eBay for $10. I was able to get someone to get it for me, and fence me a copy of the disks. Configuring Extra isn’t too involved, just set the terminal to type 4, and using the same block/destination address as all the others:

LU #3, and Model 4!

With the usual restricted I-Frame (MTU), and I turned everything on feature wise (it didn’t matter)

I had fired up both OS/2 & NT and with the same empty screen showing nothing. Next I loaded up Extra on Windows 95, and got this:

Unsupported Function
Unsupported Function

Well that was unexpected!

The 3705’s on Hercules can be connected to direclty, so I try c3270 and get this:

Wait, so my suspicion was right?!

I reset the mainframe, and then was greeted with the cat!


So what was wrong?!? I’m still not so sure, but turning off the debug on DLSw, let me see that both OS/2 AND Windows NT crash out SNASOL with an abend code of U0020.


I’m sure it means something to someone, but not to me. So this is one of those ‘dont do that if it hurts’ type things.

Since I had used Windows 95, as I figured it had more robust networking support than Windows 3.1

Setting up Windows 95 was a minor challenge as Extra! 4 is a Win16 application, and it’s DLC/802.2 support requires you to knock down the 32bit networking support to instead use the 16bit networking drivers. This is what let Extra! attach to it. Of course the following updates/files are needed for Windows 95 on Qemu:

the AMD PCnet driver is built in, so it works the best. Again, I have Dynamips & Qemu using the Microsoft Loopback as their common network, so I can do packet captures, and they both can communicate on the network.

So, of course the other question is, does it work with physical hardware?!

And YES it does!

If anything, using a terminal emulator that doesn’t crash out the host makes it seem all too easy. While I’ve seen SDLC PCI cards on ebay they are rather expensive, and does the ISA card really add anything that you could get over the LAN? Honestly no. Back in the day it really was just what you could get a hold of, and of course logically (virtually) setting stuff up made the 802.2 stuff all the easier to do, instead of leased lines, physical v35 cables, and all that other fun stuff.

With everything said & done, if you want to experience some pseudo fake SNA, go virtual. It’s far more portable, less cables involved, plus it’s self-contained making it more of a conversation piece.

All the hard work is being done by IOS, and it’s functionality like this is why cisco had established itself as king of the multiprotocol networking world. But everything is TCP/IP these days, and Cisco doesn’t commend the same enterprise place as it had once before, making this whole thing a middle point relic of the past. It’s far too new for real FEP/DLC networking, but everything now is TN32720 (telnet 3270).

I guess as a tip for people who buy physical routers is that those super expensive PCMCIA flash cards aren’t needed as long as you have enough RAM. One cool feature of the cisco routers is that the power on bootrom loads up a ‘boot’ version of IOS that is either also burned on ROM, or it’s also in FLASH. You have to remember it was super expensive back then so it may be only a few megabytes of space. The boot IOS can’t route or do anything too useful but it can load the proper IOS from various network sources into memory. My 7200 has one that supports FTP, so I could just drop IOS onto an anonymous ftp server at home.

I guess my ‘old man yells at the clouds’ is that I’ve had to deal with some bug in a remote site where the router didn’t have enough flash to store the image, and the Ethernet cards were too new for the boot IOS to drive, but we had an async card that did work, so I rebooted it to load production IOS over a T1. This one didn’t support FTP, rather it was TFTP, and it took about an hour to load. During that much time I didn’t have console access so I was getting ready to drive the 5 hours to the site, when I barely got onto the highway when I got the call that my ‘fix’ had worked and that the site was online. YAY.

I hope this has helped someone.

SDLC attempt #1

TL;DR it didn’t work, got the exact same result.

Well today was a special day, I got 2 deliveries, one PC SDLC card, and the other being the 4 port high speed serial card for my cisco 7200.

In case you were wondering what was the serial cable, its a CAB-232FC FEM DCE RS-232 cable looks like here is the DB-60 connector side:

And here is the DB-25 side.

VERY RS-232 isn’t it?

Connect the cable to the to the router! Easy!

The router doesn’t have any PCMCIA storage so I configured the thing to get it’s IOS from a FTP server.I have to say that netbooting works great.

Slot the card into the board I found in the trash that has an ISA slot, and we’re off to the races! I wanted try to replicate my NT setup, so Server 3.5 was installing when of course:

Of course this 400Mhz Celeron is going to break the lookup list as anything beyond Pentium is too much. 🙁 I just installed on Qemu instead, and used MS-DOS backup/restore. Yes it worked!

On the SNA server install, I used the IBM SDLC option hoping it was this card I’d bought. I got lucky it was!

Just like I kept it ‘leased’ and no constant RTS.

One thing to note about this SDLC card is that it takes IRQ 4 & DMA 1. So there goes any hope of a Sound Blaster or COM1. It’s not the end of the world.

And of course, I got the exact same result as last time.

I don’t know what I’m doing wrong.

I can see the serial interface up and passing traffic, and the DLSW circuit builds and is established.

I’ll either edit this with more details, or just follow up. I’m tired, and my eyes are blurry. But I thought I’d post this much to the world.

Ghosts in the mainframe!

There is a LOT going on in this image, and I’ll try to explain it, but yeah “it’s complicated”.

SNA networking & Hercules has always been a goal for a lot of people, including me as we always wanted to setup some SNA server of some kind. Especially on RISC platforms, as there is only so much fun on SQL server.

Okay I know the practical among you will say, doesn’t it support telnet 3270? Isn’t that good enough? Yes for day to day mundane stuff, absolutely. But I’m not all that interested in that, I wan’t to have the whole ancient network, and I wan’t it self contained and on my desk! Or on a laptop, as I see fit.

What started this whole adventure was a simple image from, showing that being able to connect physical devices to Hercules was indeed possible!

Image from

This is a physical IBM 3178 & 3179 terminals talking to TK4- , a MVS3.8j pre-configured system!

The magic that makes this all possible, is a cisco router, running enterprise IOS, with dlsw support.

My setup is going to be inspired by this setup, but not exactly 100% But this is what I’m going to use on Windows 10

  • Dynamips for the cisco router, running JS-M 12.2(25)S8
  • Qemu 0.90 with PCAP running Windows NT 3.51 Server along with SNA Server 2.1
  • Qemu 0.90 running Windows 3.1 and XVision
  • VMware Player
  • WireShark
  • Microsoft Loopback adapter
  • WSLv1

I had originally wanted to run the NT server on VMware but for some reason it just hangs trying to initialise the NT kernel. I didn’t bother trying to troubleshoot it, I just jumped to Qemu. Even service pack 5 didn’t help. VMware left me with the virtual network that will NAT if needed, and of course let me telnet to the Dynamips program. The SNA traffic is isolated to the MS Loopback adapter, which will let pcap programs talk to each other.

The first thing I did was run ‘hdwwiz’ on Windows 10, and added in the KM-TEST loopback adapter

We know what we want, so go to the manuall selection

Network adapters

And select the KM-TEST Loopback Adapter

Next I changed the protocols available on the loopback, as I don’t want my Windows 10 host interfering with the SNA network at all.

So the next thing to do is to get your network GUID’s. ethlist.exe from the Dynamips download will get you that:

Network devices:
  Number       NAME                                     (Description)
  0  \Device\NPF_{3DF0EC5D-7FBE-46DF-ACF8-EF5D8679A473} (loopback)
  1  \Device\NPF_{D9FBD118-B9DF-4C3C-BD9E-07A0E34D8F75} (Local Area Connection* 8)
  2  \Device\NPF_{F5057901-6A30-413A-80E4-4765DA794B7C} (Local Area Connection* 7)
  3  \Device\NPF_{E3D3EC8D-29C3-4B70-B01C-600D3F9ED1D6} (Local Area Connection* 6)
  4  \Device\NPF_{82EEDBC1-899D-416F-BD51-3DBE2287257F} (VMware Network Adapter VMnet8)
  5  \Device\NPF_{3BC364F4-5A15-405D-926C-C594383F0323} (VMware Network Adapter VMnet1)
  6  \Device\NPF_{DDF1FA94-7488-414F-A41A-EC88C1FB0DE4} (Ethernet)
  7  \Device\NPF_{E7CA8F40-4639-410D-B5CA-F402FE69AF5D} (Ethernet 2)

I want the cisco router to have two interfaces, one with TCP/IP for me to be able to telnet into it (maybe other management as well?!) and the other one for the SNA traffic.

Setting up Dynamips

As mentioned above I’m going to use the VMnet1 for TCP/IP to the router, and the loopback adapter for SNA traffic. To try to make things a little easier to read I setup a small batch file that let’s me plug in variables to Dynamips:

set loopback=\Device\NPF_{3DF0EC5D-7FBE-46DF-ACF8-EF5D8679A473}
set vmnet1=\Device\NPF_{3BC364F4-5A15-405D-926C-C594383F0323}
set IOS=c7200-js-mz.122-25.S8.bin
set NPE=npe-200
..\dynamips.exe -P 7200 %IOS%  ^
-t %NPE%  ^
-p 0:C7200-IO-FE ^
-s0:0:gen_eth:%vmnet1% ^
-p 1:PA-4E  ^
-s1:0:gen_eth:%loopback% ^

The caret symbol will break up lines on NT, much like the ampersand will on Unix. And this let’s me use clear variables for the networks, IOS & NPE type so it’s nowhere near as complicated to edit.

This will create a cisco 7200 with an NPE-200, with the following cards:

The next thing is what ip address is bound to VMnet1? This is mine:

Ethernet adapter VMware Network Adapter VMnet1:

   Connection-specific DNS Suffix  . :
   Link-local IPv6 Address . . . . . : fe80::c3d2:c891:b7e0:6797%5
   IPv4 Address. . . . . . . . . . . :
   Subnet Mask . . . . . . . . . . . :
   Default Gateway . . . . . . . . . :

So all my TCP/IP in this example will be using

As mentioned on the 9track page, all the magic happens on the cisco router. I’ve made a few changes as I may want to try the SDLC in the future to perhaps some other experiment if I can find an emulator that’ll drive it over serial, but for now let’s just get to the config:

version 12.2
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
hostname dlsw
enable password cisco
ip subnet-zero
no ip domain-lookup
ip cef
no mpls traffic-eng auto-bw timers frequency 0
call rsvp-sync
source-bridge ring-group 1
dlsw local-peer peer-id
dlsw remote-peer 0 tcp
dlsw mac-addr 4000.1020.0100 remote-peer ip-address
dlsw udp-disable
dlsw transparent switch-support
interface FastEthernet0/0
 ip address
 duplex half
 no clns route-cache
interface Ethernet1/0
 no ip address
 duplex half
 no clns route-cache
 dlsw transparent redundancy-enable 5555.5555.5000
 dlsw transparent map local-mac 4000.1020.0100  remote-mac 4000.0999.0100
interface Ethernet1/1
 no ip address
 duplex half
 no clns route-cache
interface Ethernet1/2
 no ip address
 duplex half
 no clns route-cache
interface Ethernet1/3
 no ip address
 duplex half
 no clns route-cache
interface Serial2/0
 no ip address
 encapsulation sdlc
 no keepalive
 serial restart-delay 0
 clockrate 64000
 no clns route-cache
 sdlc role primary
 sdlc vmac 4000.0999.0100
 sdlc address C1
 sdlc xid C1 01700019
 sdlc partner 4000.1020.1000 C1
 sdlc dlsw C1
interface Serial2/1
 no ip address
 serial restart-delay 0
 no clns route-cache
interface Serial2/2
 no ip address
 serial restart-delay 0
 no clns route-cache
interface Serial2/3
 no ip address
 serial restart-delay 0
 no clns route-cache
ip classless
no ip http server
dial-peer cor custom
line con 0
 session-timeout 35791
 stopbits 1
line aux 0
 stopbits 1
line vty 0 4
 password cisco

This sets up the router so I can telnet to it from my desktop at, and allows it to talk to the base Windows machine on

All the magical MAC addresses come from, as he wrote the dlsw hooks, so I just copied that. There is probably a great deal that could be cleaned up, but once I saw the two talking I kind of froze what I was doing.

With that much in place I then jumped to WSL,and built the emulator from github. I cloned it, and renamed that to herc-dlsw. At least for me this was pretty straightforward. The Hercules fork will build with Visual Studio as well, but I knew I was going to need some kind of tn3270 emulator, and I wanted to use x3270, and I had just recently bought this discounted copy of XVision, so of course I wanted to use that.

Despite this catastrophic defect that wasn’t disclosed in the auction.

I downloaded and extracted the TK4- latest distro on WSL. I just created a ‘herc’ directory in my home to house the tk4- release. The next thing to do is overlay your dlsw enabled exe’s and libraries.

cd ~/herc-dlsw/.libs
mkdir x
cp * x
cd x
rm *.o *.lai
cp *.so $HOME/herc/hercules/linux/64/lib/hercules
cp *.la $HOME/herc/hercules/linux/64/lib/hercules
rm *.so *.la
cp * $HOME/herc/hercules/linux/64

Now with the binaries in place, I do need to setup the Xvision VM so I can receive the X11. Of course there is so many other ways to do this, but this is mine:

qemu.exe -L pc-bios -m 64 -hda xvision.vmdk -net nic,model=ne2k_isa -net user -redir tcp:6000::6000

The important thing is that tcp port 6000 is redirected inwards, and that I’m using the NE2000 card, which on my weird fork will print out the hardware config, so I know how to find the nic.

added SLIRP
adding a [GenuineIntelC♣] family 5 model 4 stepping 3 CPU
added 64 megabytes of RAM
trying to load video rom pc-bios/vgabios-cirrus.bin
added parallel port 0x378 7
added NE2000(isa) 0x320 10
pci_piix3_ide_init PIIX3 IDE
ide_init2 [0] s->cylinders 203 s->heads 16 s->sectors 63
ide_init2 [1] s->cylinders 0 s->heads 0 s->sectors 0
ide_init2 [0] s->cylinders 2 s->heads 16 s->sectors 63
ide_init2 [1] s->cylinders 0 s->heads 0 s->sectors 0
added PS/2 keyboard
ps2.c added PS/2 mouse handler
added Floppy Controller 0x3f0 irq 6 dma 2
installing PS/2 mouse in CMOS
  Bus  0, device   0, function 0:
    Host bridge: PCI device 8086:1237
  Bus  0, device   1, function 0:
    ISA bridge: PCI device 8086:7000
  Bus  0, device   1, function 1:
    IDE controller: PCI device 8086:7010
      BAR4: I/O at 0xffffffff [0x000e].
  Bus  0, device   1, function 3:
    Class 0680: PCI device 8086:7113
      IRQ 0.
  Bus  0, device   2, function 0:
    VGA controller: PCI device 1013:00b8
      BAR0: 32 bit memory at 0xffffffff [0x01fffffe].
      BAR1: 32 bit memory at 0xffffffff [0x00000ffe].

And in this case it’s 0x320 IRQ 10. XVision being it’s own level of disappointment, I’ll have to cover it further, and later but suffice to say it at least catches the x3270 so I can get onto the console.

Setting up Hercules

Editing conf/tk4-_default.cnf is pretty easy as it’s on Linux and you can use VI.

0660 3705 lport=${N660PORT:=37051} locncpnm=N07 rmtncpnm=N08 …
          unitsz=252 ackspeed=1000
0661 3705 lport=${N661PORT:=37052} locncpnm=N10 rmtncpnm=N11 …
          idblk=017 idnum=00018 locsuba=10 rmtsuba=11 unitsz=252 …
0662 3705 lport=${N662PORT:=37053} debug=yes dlsw=yes locncpnm=N12 …
          rmtncpnm=N13 idblk=017 idnum=00019 locsuba=12 rmtsuba=13 …
          unitsz=252 ackspeed=1000
0663 3705 lport=${N663PORT:=37054} locncpnm=N14 rmtncpnm=N15 idblk=017 …
          idnum=0001a locsuba=14 rmtsuba=15 unitsz=252 ackspeed=1000

And it’s simple, just assign the dlsw to the 0662 3705 controller.

The real fun is in the VTAM configuration. Which had been stumping me for well over a year. But then I found this Bradrico Rigg article aptly titled : Run your own mainframe using Hercules mainframe emulator and MVS 3.8j tk4, and it gave me the confidence to get this DONE. Thanks Bradrico!

First get MVS up and running. You have to run the ‘console_mode’ script to see what is going on.

cd herc/unattended
cd ..

It’s not all that difficult XVision is using SLiRP, so it’s listening on all my IP addresses so I just do a simple

export DISPLAY=
nohup x3270 &

And the emulator will pop up in Qemu. Just connect to localhost:3270 and you’ll be greeted by the login pannel:

Credentials are HERC01 / CUL8TR

I would HIGHLY recommend following the tutorial to get used to submitting a simple COBOL program. It walks through the key concepts of locating a file, and viewing it on MVS. Something that up until yesterday was out of my league.

We need to edit the file S3705 on SYS1.VTAMLST

Basically it’s 1,3,4 from the main pannel:

or RFE, Utilities, DSLIST

Type in the Volume name, then tab over to the left of the volume and put in V to view

Now we will get a list of all the files. We want to edit S3705, so you can tab/arrow down, but sure to put an `E’ next to it, then hit enter so we can edit the file

F7/F8 will page down/page up as needed. As mentioned we are interested in Subarea 13, PU type 2.

The line we are changing is the MAXDATA or MTU size for this unit. Since we are doing dlsw, or an emulated serial link, we need to knock it down to 256. Notice all the plus signs on the right hand? THOSE ARE IMPORTANT! Not only do they need to exist, but they also have to be on the far right.

For those wondering the MTU sizes on the client side by media type are as follows: And notice that the host size is different, as this takes in account of packet headers.

Making sure to overtype the 3780, to a 256, and ensuring the + sign hasn’t moved you can hit enter, cursor to the top and type in SAVE.

We can then edit the N13 file, changing line 35 to have MAXLU=3

Hopefully this clears up editing VTAM files.

As mentioned the easiest way to regen the system is to delete the old object files. So hit f3 a few times and get back to the dataset list

This time we want the VTAMOBJ set. Go and ‘V’iew it like last time and we will get the list of files:

Now we are going to put a ‘d’ next to N13 and S3705. This will flag them for deletion. Hit enter!

The files are now gone! On the next boot they will be rebuilt.

I just hit F3 a bunch of times and it’ll drop to some TSO shell

From here you can shutdown the system. It’ll take a few minutes, but you can start it up again just the same way you brought it up. Remember to attach your console.

Setting up SNA Server

Just like Dynamips, I setup a batch file, as the default one is just far too long to read:

@echo you need to figure out your nic name..
@echo something like
set loopback=\Device\NPF_{3DF0EC5D-7FBE-46DF-ACF8-EF5D8679A473}
set vmnet1=\Device\NPF_{3BC364F4-5A15-405D-926C-C594383F0323}
qemu -m 64 -L pc-bios ^
-hda SBS15.vmdk ^
-soundhw sb16,adlib ^
-net nic,model=pcnet,macaddr=52:24:00:22:00:01 ^
-net pcap,devicename=%loopback% ^
%1 %2 %3 %4 %5 %6

This will setup a small machine with 64MB of ram, a single AMD PCNet adapter on the loopback interface. I installed Windows NT 3.51 from the Small Business Server 1.5 setup. I don’t know why VMware + NT 3.51 didn’t get along, maybe it’s my Erying, Or maybe it just plain doesn’t work, I’m not sure, and far too impatient to troubleshoot it.

It’s very important that you do add the DLC Protocol during setup. It’s in the ‘Add Software’ part. I kept my NT very simple with only NetBEUI and DLC protocols. At the moment I’m not that interested in actually networking the NT, and if I was, I would add a second NIC, just like what I did for Dynamips.

Setting up NT isn’t that interesting, but SNA server is. I did use the 2.11 on the Back Office CD, but for completeness sake of testing I tried the oldest one I could find, and 2.1 beta from June, Build

I left the network name & control point name blank as I just want terminal, I’m not even going to think that LU6.2 applications on such an ancient version of MVS was even possible.

This is pretty much default, the Link service basically sets itself up as we only have the one NIC.

Take note of the remote network address. 400010200100 which came from above the address we directly point to the dlsw. Also it’s form the 9track blog.

Insert a 3270 LU for us to try to talk to Hercules.

I’m pretty sure it was hard coded to be a model 2.

I turned off the ability for the model to be overwitten.

Create a pool, I called it swimming, because of ‘reasons’. I made it a type 2 pool and added the terminal to it.

Next I added the EVERYONE user, and gave them access to the SWIMMING pool

Finally we are ready to save the config, and do the hand holding and start up. If the stars aligned you will see them go ACTIVE/ACTIVE and the terminal will go Available.

Sadly the terminal won’t go live, it’s stuck in SSCP.

And this is as far as I can go. I have to think that with either something far older protocol wise for the PC, such as IBM Personal Communications/3270 for Windows V2.0 (v4 didnt work either), or a far newer Mainframe software version would support whatever it is SNA server wants to give us the crazy dream of running SNA self contained.

Running Wireshark on the loopback network I see this message:


Sadly this is as far as I can take you. I do want to give a special thanks to Vinatron & blackbit for trying to troubleshoot this with me. Best we can figure is that TK4- is just too old.


From the cisco router try dlsw commands like this:

dlsw>sho dlsw circuits
Index           local addr(lsap)    remote addr(dsap)  state          uptime
2281701660      4a24.0044.0080(04)  0200.9099.8000(04) CONNECTED      00:02:23
Total number of circuits connected: 1

This does show the connection. Notice that ‘show bridge’ will show nothing in this config.

Be sure to check peers as well:

dlsw>show dlsw peers
Peers:                state     pkts_rx   pkts_tx  type  drops ckts TCP   uptime
 TCP   CONNECT         10        13  conf      0    1   0 00:05:07
Total number of connected peers: 1
Total number of connections:     1

Make sure your interfaces are ‘up/up’ and passing traffic

FastEthernet0/0 is up, line protocol is up
  Hardware is DEC21140, address is ca00.48f4.0000 (bia ca00.48f4.0000)
  Internet address is
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Half-duplex, 100Mb/s, 100BaseTX/FX
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 1000 bits/sec, 2 packets/sec
  5 minute output rate 2000 bits/sec, 2 packets/sec
     12768 packets input, 1439279 bytes
     Received 3609 broadcasts (0 IP multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog
     0 input packets with dribble condition detected
     9999 packets output, 1037736 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out
dlsw>show int eth1/0
Ethernet1/0 is up, line protocol is up
  Hardware is AmdP2, address is ca00.48f4.001c (bia ca00.48f4.001c)
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:02, output 00:00:02, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     52426 packets input, 5148287 bytes, 0 no buffer
     Received 12336 broadcasts (0 IP multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 input packets with dribble condition detected
     36383 packets output, 2465490 bytes, 0 underruns
     0 output errors, 0 collisions, 3 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out

And of course check WireShark to see if there is any handshake:

And of course check the Hercules logs to make sure your VTAM rebuilt, look for ERROR or anything related to S3705 or N13.

The arrogance of Silicon Valley is astounding: or the death of 6to4

For many people across the world, and I suspect the majority the deathmarch rollout of IPv6 has been about as obtainable today as it was in the early 00’s. Absolutely no traction from ISP’s. Where I live in Hong Kong, none of the residential or even commercial connections I have access to have native v6. Instead there was this fantastic option of tunneling IPv6 into IPv4, using a technology called 6to4 which gave everyone with a registered IPv4 address suddenly had 65535 networks to build out their own massive IPv6 deployment.

Simply put 6to4 put the individual onto the map for a NAT’less IPv6 world. 6to4 allowed two IPv6 hosts to talk to each other through the IPv6 Internet backbone, with zero changes on the Internet required. It just worked.

And of course Silicon Valley knows best, and decided that this network democratization must be stopped. Power to the People is the anthesis of the megacorps.

Google DNS Primary: 2001:4860:4860::8888
Google DNS Secondary: 2001:4860:4860::8844
Cloudflare DNS Primary: 2606:4700:4700::1111
Cloudflare DNS Secondary: 2606:4700:4700::1001
Quad9 DNS Primary: 2620:fe::fe
Quad9 DNS Secondary: 2620:fe::fe:9

This is a list of some popular ‘common’ IPv6 DNS servers. Windows 10/11 (probably 8/8.1 but who uses that?!) are not only IPv6 capable but actually IPv6 native, with a preference for the IPv6 DNS servers.

TP-Link Wireless N Router WR840N choices

I have this low end TP-Link Wireless N Router WR840N router, as where I live the maximum speed is 30Mbit/10Mbit DSL. There was no point in buying anything crazy expensive. My ISP has zero IPv6 deployment. The only way I can participate is buying a tunnel, or using 6to4. So I’d been using 6to4 for a while, and things have been great. But the last while it’s been super downhill. Sadly the firmware doesn’t give an option to force IPv6 DNS, but it automatically chooses Google.

C:\Users\neozeed>ping 2001:4860:4860::8888

Pinging 2001:4860:4860::8888 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 2001:4860:4860::8888:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

And sure enough I’m getting massive timeouts, and the web had basically become utterly unusable. Fantastic.

I’d even gone through the steps of creating a local DNS server and having it VPN to the United States thinking that’d help me, as the DNS errors felt like the encroaching Great Firewall of China. However the source of all my problems just turned out to be out of touch Silicon Valley arrogance.

rfc7526 ( Deprecating the Anycast Prefix for 6to4 Relay Routers

This is where they chose to kill over IPv6 for the masses, because local firewalls work as expected.

Authors' Addresses

   Ole Troan

   EMail: [email protected]

Yeah what a surprise. And of course Google cut off IPv6. These tech giant oligarchs are not your friends.

The good news is that the other ISP’s Cloudflare & Cloud9 still honor 6to4.

Configuring IPv6 DNS on Windows 11

Windows 11 supports DNS over HTTPS, so you just need to enable it. I’m hardwired so under the settings -> network then -> Ethernet for me, maybe Wi-Fi for you?

Then just hit Edit over the DNS server assignment:

Then go ahead and pick a NON GOOGLE DNS service, and select DNS over HTTPS for the ‘ultra secure’ wave of the future.

And now your DNS will work. YAY.

Default Server:
Address:  2606:4700:4700::1111

Address:  2606:4700:4700::1111

Non-authoritative answer:
Addresses:  2404:6800:4001:800::200e

Of course you won’t be able to connect to anything from Google over IPv6, but that is the price you pay for not living in the precious Silicon Valley tech bubble.

Personally I think it’s a good thing when elitists lock themselves away from the world, and decrease their relevancy to everyone.

Obviously the end game won’t be some magical rollout of IPv6 over Asia, rather it’ll be the end of IPv6. As always the problems stemmed from the backbone, even the 512MB limit of the cisco 7200 was overcome, but NAT got around the limitations of the fixed and exhausted IPv4 network. Too bad they had to kill it, but of course it’s just because random people could just host stuff on their own network, and well network democratization isn’t what cisco et all is all about.

Running Netware 3.12 on Qemu / KVM 2.8.0

So yeah, let’s build a NetWare 3.12 server! I’ve covered this over and over and over, but heh let’s do it again!

First things first, the default position of the NE2000 card at 0x300/IRQ 9 does NOT WORK.  This is the biggest stumbling block, and time waster right there.  I loaded a PCnet driver, and it didn’t lock, but it didn’t work.  I loaded 2 ne2000’s thinking the second would come up in the correct position but that didn’t work either.  The solution of course is to dive into the parameters for QEMU to drive devices.

So for the fun of it, here is how I’m going to run this in a nested VM.  It’s also why I didn’t bother enabling the ‘-enable-kvm’ flag.  Although on a real machine I would.

qemu-system-i386 -m 16 \
-cpu 486 \
-net none \
-vnc :1 \
-device ne2k_isa,mac=00:2e:3c:92:11:01,netdev=lan,irq=11,iobase=0x320  \
-netdev vde,id=lan,sock=/tmp/local \
-hda netware312.qcow2 \
-hdb netware312_data.qcow2 \
-parallel none \
-monitor tcp::4400,server,nowait

So the key portion here is the iobase & irq.  This let’s me sidestep the IRQ 9, port 0x300 issue.  Talking to the monitor and running ‘info qtree’ I’m able to look at the parameters that I can pass the network card:

bus: isa.0
type ISA
dev: ne2k_isa, id ""
  iobase = 800 (0x320)
  irq = 11 (0xb)
  mac = "00:2e:3c:92:11:01"
  vlan = 
  netdev = "lan"
  isa irq 11

As you can see there is actually a few further things I could have set, but the key ones here being the iobase, the irq, the mac address, and then assigning it to a netdev, in this case I then bind it to a VDE.

Now the fun part goes back to the old days of Netware when your network could run several possible frame times.  If you have 2 machines with different frames, they will not see each-other.  it was a cheap way to hide networks well until the wide spread availability of sniffers.  Naturally cisco and Novell have different terms for the same things.  Below are the ones that are relevant to Ethernet:

[table id=1 /]

So in my case on my Netware server I simply load my NE2000 like this:

BIND IPX TO NE2000 NET=800852

Next on my cisco router I simply need:

ipx routing ca00.06a3.0000

interface FastEthernet0/0
ipx network 800852

And now I can see my server from the router:

HKOffice#sho ipx servers
Codes: S - Static, P - Periodic, E - EIGRP, N - NLSP, H - Holddown, + = detail
U - Per-user static
1 Total IPX Servers

Table ordering is based on routing and server info

Type Name Net Address Port Route Hops Itf
P 4 HONGKONG 852.0000.0000.0001:0451 2/01 1 Fa0/0

And the interface looks busy on NetWare

NetWare 3.12

NetWare servers advertise their internal networks, much like how people should be using loopback adapters in OSPF, or EIGRP … So if you check the IPX routing table, you’ll see the wire route to the internal network:

HKOffice#sho ipx route
Codes: C - Connected primary network, c - Connected secondary network
S - Static, F - Floating static, L - Local (internal), W - IPXWAN
R - RIP, E - EIGRP, N - NLSP, X - External, A - Aggregate
s - seconds, u - uses, U - Per-user static/Unknown, H - Hold-down

2 Total IPX routes. Up to 1 parallel paths and 16 hops allowed.

No default route known.

C 800852 (NOVELL-ETHER), Fa0/0
R 852 [02/01] via 800852.002e.3c92.1101, 150s, Fa0/0

Just like that!

One thing to note, on VDE, I had an issue where the NetWare server takes about a minute before it’ll see traffic.  It could be my IOS for all I know…..

4.3BSD syslogd for Windows

Continuing from my TACACS adventure, I also thought it would be nice to capture syslogs, and save them. Oddly enough this is a big business, with even low end products like Kiwi Syslog server costing some $295 USD!

Well that’s too much for me, so I figured that the most wide spread at the time must have been the 4.3BSD syslogd, so I’ll start with that.

Just as before this was a pretty straight forward port, I had to remove all the /dev/kmem and UNIX socket stuff, as they obviously don’t exist on Windows.  Just as the same, you can’t “write to users” to send messages, so by default output is a file.  I suppose I could use the net send functionality to pop up a message, but I find it just as annoying today as it was then.

At any rate in no time I was able to setup a simple config file, and then get my router to turn on full logging & enable full debugging to get a continuous stream of messages.  The only ‘gotcha’ is that this sylogd wants to be able to do reverse lookups, so you really ought to have a DNS with reverse entries, or a good hosts file.

syslogd_win32 -d
off & running....
cfline(*.emerg;*.alert;*.crit;*.err;*.warning;*.notice;*.info;*.debug   log.txt)
7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 X FILE: log.txt
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 UNUSED:
logmsg: pri 56, flags 8, from jaderabbit, msg syslogd: restart
Logging to FILE log.txt
syslogd: restarted
logmsg: pri 277, flags 0, from testcisco, msg 2458: 00:24:19: SNMP: HC Timer 619E3D1C fired
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2459: 00:24:19: SNMP: HC Timer 619E3D1C rearmed, delay = 5000
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2460: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2461: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2462: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2463: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2464: 00:24:22: SNMP: HC Timer 61875370 fired
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2465: 00:24:22: SNMP: HC Timer 61875370 rearmed, delay = 20000
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2466: 00:24:22: IP: s= (FastEthernet0/0), d= (FastEthernet0/0), len 159, rcvd 3
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2467: 00:24:22: UDP: rcvd src=, dst=, length=139
Logging to FILE log.txt
logmsg: pri 277, flags 0, from testcisco, msg 2468: 00:24:22: IP: s= (FastEthernet0/0), d=, len 159, dispose udp.noport
Logging to FILE log.txt

As you can see, running it in debug mode tells me what is going on.  And the log.txt file contains a nicely formatted log file, just the way that it was done on BSD:

Apr 13 13:11:04 jaderabbit syslogd: restart
Apr 13 13:11:17 testcisco 2458: 00:24:19: SNMP: HC Timer 619E3D1C fired
Apr 13 13:11:17 testcisco 2459: 00:24:19: SNMP: HC Timer 619E3D1C rearmed, delay = 5000
Apr 13 13:11:27 testcisco 2460: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Apr 13 13:11:27 testcisco 2461: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Apr 13 13:11:27 testcisco 2462: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Apr 13 13:11:27 testcisco 2463: 00:24:21: IP: s= (FastEthernet0/0), d=, len 202, dispose ip.hopcount
Apr 13 13:11:27 testcisco 2464: 00:24:22: SNMP: HC Timer 61875370 fired
Apr 13 13:11:27 testcisco 2465: 00:24:22: SNMP: HC Timer 61875370 rearmed, delay = 20000
Apr 13 13:11:34 testcisco 2466: 00:24:22: IP: s= (FastEthernet0/0), d= (FastEthernet0/0), len 159, rcvd 3
Apr 13 13:11:34 testcisco 2467: 00:24:22: UDP: rcvd src=, dst=, length=139
Apr 13 13:11:34 testcisco 2468: 00:24:22: IP: s= (FastEthernet0/0), d=, len 159, dispose udp.noport


I’m sure it’s full of other bugs, but all I tested was that I could log to a file, and it’s doing that much just fine.  If you feel so inclined you can download & compile it, the source is: syslogd_win32.c

TACACS for Windows

So, in my fun and excitement I was putting together a ‘cisco’ network using dynamips that spans a few sites across the world.  I’m using ancient copies of NT for some servers, although I plan on adding in some 386BSD, SunOS SPARC, and maybe even 68010 based, along with other stuff.

I have the routers running fine, but I felt like adding some kind of external authentication service, and TACACS certainly fits the bill!  And to be all vintage as usual, I’m not going to use TACACS+ as it’s simply too new, and too big.  So first things first, I need a copy of the source to TACACS as I’m certainly not going to write my own!  I found this directory on which has a bunch of old cisco related material, and sure enough there is a tacacsd.c

Even better it’s from 1989 which suits my need for something positively ancient, and simple enough to be a single C file.

 * TACACS daemon suitable for using on Un*x systems.
 * Janruary 1989, Greg Satz
 * Copyright (c) 1989 by cisco Systems, Inc.
 * All rights reserved.

Porting it to run on Winsock, really wasn’t all that hard, I had it running as a standalone program within a few minutes, however there is no password file in NT, so as a simple test, I had simply short circutied the username lookup to always suceeded, along with a password compare.

Since I have VMWare Player installed on my machine, I can use the VMNet 8 connection to talk to my host computer.  The hard part of course is trying to figure out which NIC is which, but dynamips -e will give you a list like this:

Cisco Router Simulation Platform (version 0.2.16-experimental(merge uppc smips)Build-1-x86/MinGW stable)
Copyright (c) 2005-2011 Christophe Fillot.
Build date: Dec 15 2016 04:20:41

Pcap version [WinPcap version 4.1.3 (packet.dll version, based on libpcap version 1.0 branch 1_0_rel0b (20091008)]
Network device list:

   \Device\NPF_{D3DF08C4-7A33-4FE2-9351-000153705A30} : VMware Virtual Ethernet Adapter
   \Device\NPF_{3FB194EF-F3A4-45F2-AFAB-A4ABA98E8FF7} : Qualcomm Atheros Ar81xx series PCI-E Ethernet Controller
   \Device\NPF_{C46B48B8-74E1-4938-9BFE-E407949A7940} : Microsoft
   \Device\NPF_{F72C65CD-C6BC-44FE-9019-C5057DB1D9AB} : VMware Virtual Ethernet Adapter
   \Device\NPF_{CE75B9C1-8189-4C8F-8EF6-6CEB0C6D0329} : Microsoft
   \Device\NPF_{737A8B62-9A87-4739-9CC2-BF05CDC315D0} : Microsoft

And with that information, we are good to go!  Since I’m doing a simple test here, I don’t need anything other than a single ethernet to talk to my host, so here is a VERY simple cli to run dynamips:

..\dynamips.exe -P 7200 ..\c7200-is-mz.19991126.bin -t npe-200 -p 0:C7200-IO-FE -s 0:0:gen_eth:\Device\NPF_{D3DF08C4-7A33-4FE2-9351-000153705A30}  –idle-pc 0x604f1da0 -X

And I’m off booting!

Cisco Router Simulation Platform (version 0.2.16-experimental(merge uppc smips)Build-1-x86/MinGW stable)
Copyright (c) 2005-2011 Christophe Fillot.
Build date: Dec 15 2016 04:20:41

Pcap version [WinPcap version 4.1.3 (packet.dll version, based on libpcap version 1.0 branch 1_0_rel0b (20091008)]
Idle PC set to 0x604f1da0.
IOS image file: ..\c7200-is-mz.19991126.bin

ILT: loaded table "mips64j" from cache.
ILT: loaded table "mips64e" from cache.
ILT: loaded table "ppc32j" from cache.
ILT: loaded table "ppc32e" from cache.
CPU0: carved JIT exec zone of 64 Mb into 2048 pages of 32 Kb.
C7200 instance 'default' (id 0):
  VM Status  : 0
  RAM size   : 256 Mb
  IOMEM size : 0 Mb
  NVRAM size : 128 Kb
  NPE model  : npe-200
  Midplane   : vxr
  IOS image  : ..\c7200-is-mz.19991126.bin

Loading ELF file '..\c7200-is-mz.19991126.bin'...
ELF entry point: 0x80008000

C7200 'default': starting simulation (CPU0 PC=0xffffffffbfc00000), JIT enabled.
mips64_test.s ROMMON emulation microcode.

mips64_test.s Launching IOS image at 0x80008000...
Self decompressing the image : ####()## [OK]

              Restricted Rights Legend

Use, duplication, or disclosure by the Government is
subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.

           cisco Systems, Inc.
           170 West Tasman Drive
           San Jose, California 95134-1706

Cisco Internetwork Operating System Software
IOS (tm) 7200 Software (C7200-IS-M), Experimental Version 12.0(20000110:181554) [otroan-thanksgiving-rel 175]
Copyright (c) 1986-2000 by cisco Systems, Inc.
Compiled Thu 20-Jan-00 15:07 by otroan
Image text-base: 0x60008900, data-base: 0x613D0000

cisco 7206VXR (NPE200) processor with 253952K/8192K bytes of memory.
R5000 CPU at 200Mhz, Implementation 35, Rev 1.2
6 slot VXR midplane, Version 2.1

Last reset from power-on
Bridging software.
X.25 software, Version 3.0.0.
1 FastEthernet/IEEE 802.3 interface(s)
125K bytes of non-volatile configuration memory.
4096K bytes of packet SRAM memory.

65536K bytes of ATA PCMCIA card at slot 0 (Sector size 512 bytes).
8192K bytes of Flash internal SIMM (Sector size 256K).

         --- System Configuration Dialog ---

Would you like to enter the initial configuration dialog? [yes/no]: no

Press RETURN to get started!

Next I need to take note of how VMWare & Windows have configured my VMNet8 adapter, and configure the router accordingly:

Ethernet adapter VMware Network Adapter VMnet8:

   Connection-specific DNS Suffix  . :
   Link-local IPv6 Address . . . . . : fe80::fcd4:2983:bcba:2d63%19
   IPv4 Address. . . . . . . . . . . :
   Subnet Mask . . . . . . . . . . . :
   Default Gateway . . . . . . . . . :

So Im using so let’s setup the router.  Let’s give it a .10 for the heck of it.  Also I’m going to turn off DNS name resolution for the moment.

00:00:02: %DEC21140-3-DUPLEX_SPEED: FastEthernet0/0 doesn't support the configured duplexand speed combination
00:00:02: %DEC21140-3-DUPLEX_SPEED: FastEthernet0/0 doesn't support the configured duplexand speed combination
00:00:02: %DEC21140-3-DUPLEX_SPEED: FastEthernet0/0 doesn't support the configured duplexand speed combination
00:00:32: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down
00:00:32: %SYS-5-RESTART: System restarted --
Cisco Internetwork Operating Sys
Router>tem Software
IOS (tm) 7200 Software (C7200-IS-M), Experimental Version 12.0(20000110:181554) [otroan-thanksgiving-rel 175]
Copyright (c) 1986-2000 by cisco Systems, Inc.
Compiled Thu 20-Jan-00 15:07 by otroan
00:00:33: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down
Router#config t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#int fa0/0
Router(config-if)#ip address
Router(config-if)#no shut
Router(config)#ip route
00:01:29: %DEC21140-3-DUPLEX_SPEED: FastEthernet0/0 doesn't support the configured duplexand speed combination 
00:01:31: %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up
00:01:32: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
Router(config)#no ip domain-lookup
Building configuration...
00:01:39: %SYS-5-CONFIG_I: Configured from console by console

And if everything is going well, I can now ping from Windows!

Microsoft Windows [Version 10.0.14393]
(c) 2016 Microsoft Corporation. All rights reserved.


Pinging with 32 bytes of data:
Reply from bytes=32 time=54ms TTL=255
Reply from bytes=32 time=31ms TTL=255
Reply from bytes=32 time=31ms TTL=255
Reply from bytes=32 time=31ms TTL=255

Ping statistics for
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 31ms, Maximum = 54ms, Average = 36ms


Awesome!  Pinging from the cisco however fails.


Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Success rate is 0 percent (0/5)

This fails as Windows by default has it’s firewall on, which then blocks all incoming traffic. However to see that the ICMP would have succeded, you can look at the arp table, and the .1 address should have been learned:

Router#show arp
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet           0   0050.56c0.0008  ARPA   FastEthernet0/0
Internet          -   ca00.3730.0000  ARPA   FastEthernet0/0

We can either diable the firewall, or we can add a rule to permit ICMP. To do either you need to go to the firewall control panel in Windows.  In this quick example, I’m going to build a rule using the firewall control pannel.

So hit the advanced settings to the left.

Click on the ‘Inbound Rules’, and now we are going to create a new rule.

Select a Custom Rule

Allow ‘All Programs’

Then set the protocol to ICMPv4

Now we can select the scope of the rule, in this case we are going to allow the network to pass icmp traffic to us.  Add it as a source and destination.

In this quick example I’m applying it everywhere.  I suppose a better  setup would be to make sure the VMNet 8 adapter is a ‘Private’ network, and ONLY apply this to the Private domain.

Then give it a name, something like ‘ICMP for VMnet8’


Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to, timeout is 2 seconds:
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/30/36 ms

And now we can ping!

Now for the fun, I go ahead and compile my hacked up tacacsd.c, and run it, and then permit it to run on all networks:

And now I can configure the router to use TACACS.  Keep in mind, once gain that this is *NOT* TACACS+ so this is done a little differently.  I’m going to simply set TACACS for telnet connections.

Router#config t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#tacacs-server host
Router(config)#line vty 0 4
Router(config-line)#login tacacs
Router(config)#enable password 0 cisco
Building configuration...
00:01:28: %SYS-5-CONFIG_I: Configured from console by console

And now I’m ready to test!

User Access Verification

Username: user
    Line       User       Host(s)              Idle       Location
   0 con 0                idle                 00:01:11
*  2 vty 0     user       idle                 00:00:00

  Interface  User      Mode                     Idle Peer Address


As you can see I logged in as ‘user’ … and keep in mind my TACACS simply permits anything. As for what tacacsd runs by default:

server starting
using port 12544
validation request from
query for user (pw->pw_gecos) accepted

It’s not exciting, but as you can see it is attempting to look through the gecos to verify the user, but in this case I just allow anything.  And besides just granting anyone the ability to login, let’s take a look on the wire:

WireShark capture of TACACS traffic

As you can see the username & password go over the wire in plain text.  Even the response is simple enough to decode:

Access granted!

Needless to say this is something that you would NEVER EVER EVER run in a real network.  Of course a system that sits on telnet is vulnerable anyways, but I suppose a TACACS server that lets anyone log in, makes either a VERY trusting network, or a good honeypot.  Against my better judgement, here is tacacsd_win32.c  Naturally it could be easily made to verify passwords against pretty much anything.

Getting started with cisco VIRL L2 virtual Ethernet switches

Well for the longest time there was no generally available way to emulate a cisco L2 switch. right before Dynamips was abandoned, in 0.28RC1, there was actually some work on the the Catalyst 6000 Supervisor 1 line card, although no interfaces are supported, and it was largely seen as impossible at the time.

While there may have been leaks of the internal IOU or IOS on UNIX, these are even more dubious than buying your own cisco 7200 and running that IOS on Dynamips.  Indeed in the old days you’d no doubt find people with home labs that look something like this:

My sad lab.

So yeah, I know it’s not new but it was new to me.  But yes, VIRL is something us mere mortals can buy without a CCIE on hand, or a multi-million dollar contract on hand.  Although it isn’t free, but compared to everything else cisco sells it’s cheap…

So VIRL comes in a few different flavors.  They do have an ISO to run on bare metal x86 machines, OVAs for deployment on VMWare Workstation, and ESXi (Although for player you’ll have to get VIX and the vmnet config util from workstation, as I went through here & here).

Although that’s not so much what I’m interested in.  As always I’m more interested in something that lets me run it on my own.

Downloading the l2 image

So as of today, the latest file is vios_l2-adventerprisek9-m.vmdk.SSA.152-4.0.55.E, with the MD5 checksum of 1a3a21f5697cae64bb930895b986d71e.

So as a first test, you can run the L2 image with Qemu/KVM!  I found it works better renaming vios_l2-adventerprisek9-m.vmdk.SSA.152-4.0.55.E to vios_l2-adventerprisek9-m.vmdk.SSA.152-4.0.55.E.vmdk otherwise there was some issues with Qemu picking up the image.

The command line for a switch can be a little crazy so it’ll break some of it up onto separate lines.  This way you can see that I bound a few interfaces to listen on UDP, while most of them are unbound, but you get the idea.  Naturally it being a cisco product, it drives with a serial console.

-m 768M
-smp cpus=1
-boot order=c
-drive file=vios_l2-adventerprisek9-m.vmdk.SSA.152-4.0.55.E.vmdk,if=ide,index=0,media=disk
-serial telnet:,server,nowait
-monitor tcp:,server,nowait
-net none -device e1000,mac=00:2e:3c:92:26:00
-device e1000,mac=00:2e:3c:92:26:01,netdev=gns3-1
-netdev socket,id=gns3-1,udp=,localaddr=
-device e1000,mac=00:2e:3c:92:26:02
-device e1000,mac=00:2e:3c:92:26:03
-device e1000,mac=00:2e:3c:92:26:04
-device e1000,mac=00:2e:3c:92:26:05,netdev=gns3-5
-netdev socket,id=gns3-5,udp=,localaddr=
-device e1000,mac=00:2e:3c:92:26:06 -device e1000,mac=00:2e:3c:92:26:07
-device e1000,mac=00:2e:3c:92:26:08 -device e1000,mac=00:2e:3c:92:26:09
-device e1000,mac=00:2e:3c:92:26:0a -device e1000,mac=00:2e:3c:92:26:0b

In some ways, this is very much like running Solaris on QEMU via a serial console.  Once booted up, if you grab the console you’ll see:

l2’s grub console

Now, while I think it’s interesting to play with, but I know many people don’t like to setup and run a dozen programs manually, so how do we get this to run under GNS3!

As of right now the current version is 1.5.3, so let’s step through this real quick

Version 1.5.3

First when you fire it up (by default) you’ll get the option to specify using a local server

use local server

Next you will want to check the box to add a Qemu VM

Add a Qemu VM

give it a name like adventerprisek9-m.vmdk.SSA.152-4.0.55.E… Or anything else you wish to call it.

give it a name

Next I set the emulator to qemu-system-i386.exe and give it 768MB of RAM.

set the Qemu emulator & RAM

hit next, and then it’ll prompt to select a disk image.  In this example, remember I had renamed the downloaded VIRL image to have a VMDK extension.

select the image

Then GNS3 will prompt to add it to the default images directory

add it to the images directory

After that the wizard is complete.

Then finish

However there is still a bunch of settings that still need to change.  If you don’t make these changes you’ll have a switch with a single Ethernet port, and you will only be able to deploy a single switch, so that won’t be any fun!.

Once the wizard has finished you’ll be in the Preferences.  Just hit edit, on the template we just added, or otherwise it’s under Edit->Preferences.

Hit edit

First thing is kind of cosmetic, but go ahead and set the Category to Switches, so that way it ‘flows’ nice in the UI.

set category

Next hit the Network tab, and then add some adapters.

set the adapters to something more usable like 12

I’ve set the switch to 12 adapters.  The default of 1 isn’t too useful.  Next up hit the Advanced settings tab.  Be sure to un-check the ‘Use as a linked base VM’ . This will let you deploy multiple copies.  On Windows there is some weird issue where changes are seemingly not saved, so be sure to have a config backup strategy beyond saving the config locally.

uncheck the Use as linked base VM

Great, hit OK, and now we’ve got our L2 template for GNS3!

As a bonus, I put it on Linux, and it’ll run under KVM, however if you use the cisco downloaded files, you’ll see this error while booting:

-Traceback= 1DBB7C8z 8DBFE5z 90522Ez 904F50z 904D5Dz 900F45z 901B7Bz 901B0Fz 8D7C0Dz 8D7B0Dz 887061z 8BAE73z 8B9FD7z 8B7827z 8BCCC4z 8C0587z – Process “Async write process”, CPU hog, PC 0x008D7D62

Over and over, and it’ll be generally slow.  For some reason KVM/Qemu on Linux is struggling with the VMDK.  So the solution is to simply convert it from a VMWare VMDK into a Qcow2 image with:

qemu-img convert -f vmdk -O qcow2 vios_l2-adventerprisek9-m.vmdk.SSA.152-4.0.55.E.vmdk  vios_l2-adventerprisek9-m.vmdk.SSA.152-4.0.55.E.qcow2

Now using the qcow2 file, the switch will boot up just fine!

For any reference I’m running Ubuntu 16.10

and the KVM version is:

# kvm –version

QEMU emulator version 2.6.1 (Debian 1:2.6.1+dfsg-0ubuntu5.3), Copyright (c) 2003-2008 Fabrice Bellard

cisco router spotted in the wild with over 20 years uptime

On this thread on reddit, bhoskins has just posted screen shots of a cisco 2514 featuring 2 10mbit Ethernet ports, and 2 2Mbit Serial ports, and just over 20 years of uptime.

cisco 3000 router with 20 years of uptime

cisco 2514 router with 20 years of uptime

As bhoskins mentions later on in the thread:

I think i probably agree especially considering that’s monthly generator exercises that include transitions from commercial -> battery -> generator power and back.

However…The config… This routers goal in life is to provide management connectivity to some equally ancient SONET equipment that doesn’t even speak IP; it only knows CLNS. That’s right kiddos, it’s a hold over from a time long ago when dinosaurs roamed the earth and there was a competing protocol to IP.

So it runs CLNS and routes it with ISIS between the core and SONET ring. The level-2 database is close to 500 LSP and there are probably on the order of 800 CLNS routes. Oh yeah and it runs IP too so the router itself can be managed. All that with it’s little 608030 CPU and 16MB of memory. That fact that none of those processes have crapped on themselves in 20 years in a router with such limited resources is impressive to say the least.

Pretty amazing stuff.  And of course there was also that Netware server with 16 and a half years of uptime.  It’s amazing on one hand how this older stuff can keep on going, and how dangerous it is security wise to run such dated stuff.

IPIP tunnel to SLiRP

I know this is what 99.99% of people hope I never do, but let’s make an incredibly insecure VPN! yay!


So the thing is that I have a cisco router and I’d love for it to connect to some Windows machine over an existing OpenVPN, and NAT out the Windows side.  Except for getting the VPN installed, they won’t give me anything else.  And they SURE as heck won’t let me connect a cisco router up…..

So first things first, I need to configure my cisco router for an IPIP tunnel, to my test Windows machine, and use the SLiRP default addresses:

interface Tunnel0
description “SLiRP tunnel”
ip address
ip mtu 1452
tunnel source GigabitEthernet0/1
tunnel destination
tunnel mode ipip

Now to start programming.

Well then I went looking and found this fun filled page, about calling winioctl’s myself, and getting winsock to do all kinds of fun things.  Namely how IPIP actually works, as it’s is it’s own protocol (none of that pesky TCP/UDP it’s IPIP!) and more importantly I can receive the traffic.

So looking at a quick UDP client/server I figured out that I can modify that so instead of listening with UDP like this:

if((s = socket(AF_INET , SOCK_DGRAM , 0 )) == INVALID_SOCKET)

I can instead call for a RAW socket, and listen on protocol #4 aka IPIP.

if((s = socket(AF_INET , SOCK_RAW , 4 )) == INVALID_SOCKET)

One caveat I had on this, is that you need to run as Administrator on the Windows machine to create raw sockets.  If you don’t have administrator privleges you’ll get this error:

Could not create socket : 10013socket() failed with error code : 10013

Now add in some nonblocking, and feed the data into SLiRP, and I got invalid data!  Using wireshark I can see that I only receive the IP portion of the data, so no hardware frame, but what is more interesting is that I receive ALL of the IP information so I get the IP+IP+DATA.  So I have to forge a L2 header, and cut out the first IP header.  I did this by cheating, using the following for a L2 header:


I then just memcpy that to the start of my buffer, then copy in the rest of the received data like this:


And now I can forge data going to SLiRP to make it happy!

And sending replies didn’t make wireshark happy at all, as there is an L2 header in there, that just doesn’t make sense in L3 space, so I trimmed that with the following:


Putting it all together

And now much to my amazement I can ping SLiRP from my 7206!

IPIP Ping!

Ok, I know what you are thinking. ICMP is great, but how about TCP?  Can I actually use this thing?

I add a route to my BBS over the SLiRP tunnel, with a simple route statement:

ip route

and then telnet…

Telnet to my BBS over IPIP to SLiRP

So yes, it does actually work!\

I don’t think anyone will ever want to use this, but for me it’s 100% novelty in that I could.

Executable & source code is here, ipip.7z.

I suppose later I could look at ipdecap, to work out how to work with GRE.