After much fighting, and apparently being blocked by one of my ISP’s, I got back onto HECnet!  Even better I was able to verify operation with HECnetNT!

Like last time I was able to bind Pathworks 32’s DECnet onto a MS Loopback adapter, and then use the bridge to connect onto that loopback to a local Linux bridge (which is also hosting a virtual SIMH VAX instance).

The big problems I ran into is that I originally had setup SIMH to use a tap interface, and connect into a bridge, as mentioned on the raspberrypi.org forums, however the HECnet bridge program seems to have difficulty injecting packets onto the bridge interface.  I suspect the ‘correct’ thing to do is to remove libpcap from the bridge, and re-write it to be a tuntap client.  There is enough examples, I should be able to do this, but I just wanted the thing to work, so I didn’t want to tackle this just yet.

Instead I had SIMH attach to the Linux lo adapter (typically where 127.0.0.1 lives), and the HECnet bridge program, and success!  Even better the interface has been up now over 12 hours since it was brought online.

Well wasn’t that fun?

Want to learn more about HECnet?  simply check it out!  But as the short order goes it’s a hobbyist DECnet of machines spread out across the globe running the ancient DECnet protocol on various legacy style systems.