Sun 4.x bug?

[Jeremy Greene]

We have a bunch of Sun SPARCstations running 4.1 and 4.11. We run an
application we wrote which uses the socket interface to both TCP and
UDP along with a timer using the SIGALRM signal. All processing of
network traffic is done using select.

All of our systems not running the above application, are just fine.
The ones running the application 'hang' at varying rates, any where
from a couple of times a week to a couple of times a day. When the
systems hang, they just don't do anything (not even respond to a
network rlogin, although oddly enough, ping does respond most of the
time). Most of the time if you're persistent, the L1-A key will
eventually get to the firmware prompt, but it does take a while, and
then all you can do is re-boot.

The question is, is there a known problem with Sun's OS pertaining to
network access? Has anyone else run into this problem, and maybe have
some guidance?

Also, if there is another list I should send this out on, please
recommend it.

Thanks
   Jeremy