As of today, ReactOS is using lwIP as its TCP library. There were a few bugs we encountered when implementing lwIP. I reported a bug related to the TF_FIN flag which caused data loss during some of our unit tests. Even so, it is much more stable than our OSKit-based TCP library. It has also performed much better than I expected. We performed several stress tests involving simultaneously hosting an HTTP server, telnet server, and chargen server, while browsing the web in Opera 9.6. The library performed exceptionally even when all of the servers were under load by multiple users. The library had no problem managing many connections during our Bit test. It managed 2.3 MB/s down on the test which is very similar to what I would get on a traditional Windows installation on my Internet connection (not to mention networking overhead from the virtual machine ReactOS was running in). You all have done great work and I hope to see it continue.
Thanks,
Cameron Gutman