I apologize if current-users isn't a place for this kind of thing.
The following was tossed on fj.os.386bsd, forwarded from a linux group...:

<<included message begins here>>
]Newsgroups: comp.os.linux.networking
]From: iialan@iifeak.swan.ac.uk (Alan Cox)
]Subject: Re: freeBSD and Linux networking code (what is different?)
]X-Nntp-Posting-Host: iifeak.swan.ac.uk
]Organization: Institute For Industrial Information Technology
]Date: Tue, 30 May 1995 16:39:59 GMT
]
]In article <3pnmm5$i82@felix.seas.gwu.edu> ryentis@seas.gwu.edu (Richard D. Yentis) writes:
]>I am wondering what are the differences between the two versions of
]>BSD and the Linux networking code.  Are they all exactly the same?
]>are Linux and freeBSD the same but the other BSD is newer and/or
]>better?  Is there a historical tie between the code?  Can someone
]>point out who I might ask to find out?
]
]NetBSD uses the BSD NET/2 code, from 4.3 BSD series kernels. This is not
]stunningly fast, not stunningly clever, has some odd quirks but is
]incredibly reliable due to its age and design.
]
]FreeBSD uses the BSD NET/3 code, from 4.4 BSD. This has some pretty serious
]bugs but has good multicast support and other niceities like TCP PAWS
]support. Most but not all of the bugs are in unusual events. It has most
]of the odd limitations of BSD NET/2 as well - eg not being able to use
]RAW sockets to listen to a protocol the kernel understands.
]
]Linux uses its own scratch written code. As of 1.2.x the code is as reliable
]as BSD (imho), and I run things like a big web server on it. Its also got
]some odd quirks and as few bugs and limitations. In theory it has the scope
]to be faster on PC hardware than the others, but optimisation to really
]make it rip is a 1.3.x project
]
]Alan
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I usually don't believe what linux people have to say about BSD, for
they seem to say a lot of bogus things about it.  Is this one of those
things, or is NetBSD's NFS code in fact based on Net/2, rather than
4.4 Lite? (not that it's a big deal or anything, since I don't use NFS
on my NetBSD box)

I appreciate if anyone could set me straight.

Ken