The Solaris manpage says:
NOTES There is currently no backlog limit.
/ Marcus Comstedt (ACROSS) (Hail Ilpalazzo!)
Previous text:
2003-01-22 17:19: Subject: Re: Stdio.port listen() backlog again...
The maximum is 128 on Linux. The man page mentions that it's only 5 on BSD and some derived systems.
/ Martin Stjernholm, Roxen IS