I was able to get my Macintosh 512K web server running and on the internet for current RetroChallenge.  It is running System 2.0/Finder 1.1g  with 64K ROMs.  Here is a link to my web page with a link to the server.:

http://apple-crapple.blogspot.com/2015/01/mac-512k-on-internet.html

It is still running the default lwIP web page.

I am pretty close to getting it to run in 128K, but it is still a little too big. It runs easily in a virtual 256K Mac.

Let me know how well, or if, it works.