So I got this request to add in some SLiRP to Previous, the NeXT computer emulator. Â Sadly work got in the way, and I trashed my windows dev machine. Â To make it worse I also trashed my MacBook Air, but with a bit of screwing around I got X-code removed, and re-installed.
So Here is my wonderful work, some 50 lines of code + the SLiRP from Cockatrice all hacked up.
ICMP to 10.0.2.2 seems to work fine, UDP seems to not work, so no DNS. Â I don’t know why either. Â I can telnet to my BBS just fine, which is about all the testing I’ve done.

Previous to the BBS
Inbound TCP seems to be broken too, but I could be initializing slirp_redirect incorrectly too.
In case you want to follow up on this the NeXT computer forums is the place to be. Â Networking with NeXTSTEP is involved.
And for anyone who want’s my files, the source is here, and an OS X 10.10.3 binary is here. Â Be sure to install the SDL2 framework ahead of time!