network hangs after about 8 hours of uptime

[Slawek]

Hello!


I used to use very old Pentium 100 with Free BSD 4.x as a gateway for our
home network and decided a few days ago to switch to Pentium Celeron system
(worked under Windows before without any issues) with Free BSD 5 (current).

The main reason behind this change was my plan of experimenting with MONO in
near future (Linux / Unix .NET Framework implementation) and the old machine
had only 32 MB of RAM.

Unfortunatelly it looks like my new Free BSD installation "hangs" just about
8 hours after boot each time.

Please note that this is not a hard hang, but I'll mention what this
computer has installed first:
- Pentium Celerom 500 MHz
- 512 MB RAM
- VIA chipset
- two built-in RS ports - one used for modem and the other for smart UPS
- PCI hardware modem used as fax (using hylafax)
- two Ethernet cards (Realtek)
- new 120 GB HDD (ATA)
- very old CD-ROM
- an old AGP video card, I don't have normally monitor attached so I prefer
to do any required debugging remotely if possible

Software running on the machine:
- sshd
- qmail
- apache 2 (with php 4)
- inetd (smtp, pop3, ftp)
- squid
- named 9
- linux binary compatibility
- ppp daemon (ppp_enable in rc.conf)

Each time when about 8 hours from boot passes I cannot connect to the
machine anymore, but if I were already connected by SSH, the connection
stays active and I can issue commands (I can't open any incoming nor
outgoing TCP nor UDP connections).

If I try to interactively open outside connection (or use some domain name
which would open outgoing UDP connection), the command hard hangs - ^C
doesn't break it - even for ping: I can ping by IP, but trying to ping by
domain name totally hangs ping.

Cron jobs stops working after the hang (there are no log entries saying
"cron" has launched "atrun").

Establishing new TCP connections works, but no data can be transmitted in
either direction.

If I configure firewall to "log and block" some packets from internal
machines I can try to send those packets after the hang and those are
logged.

I have disabled firewall just in case this were some problem with stateful
firewalling - but still hangs.

I have disabled USB, still hangs.

Oh, and something more - if I issue a "reboot" command after the "hang",
from already opened SSH connection, the SSH connection is not closed, but
just hangs, and reboot is *not* done (but fsck is not launched after hard
reboot, so is looks like disk is synced).

I haven't found anything interesing logged after the hang (the only
suspicious thing is lack of "atrun" launched entries).


Any ideas?

Any configurartion files / logs should I attach?


thanks for any help,
Slawek Piotrowski

(I've scheduled "reboot" every 6 hours as a workaround, but I'd prefer to
fix it somehow)