External connection fails after exactly 1 hour
 

I'm trying to set up a Debian "sarge" gateway with a 2.6.8-2-686 kernel. But the external connection(DHCP) with my ISP keeps failing after exactlyt 1 hour. I guess this has something to do with DHCP. But i can't find anything strange in the logs. When i reboot everything is fine for 1 hour. When i do "dhclient eth0" connection comes up again to. I tried to make a cronjob with that command, but after a while i end up with dozens of dhclients running. By the way, same problem happens with and without iptables firewall.

Anybody know what's wrong?

How do you connect to your ISP? Looking at your message I noticed you were using eth0, which would mean you are connecting over an ethernet cable to something. My question mainly will center on where you are getting your IP address from.

I have 3 nics in my gateway. Eth0 connects to my adsl-modem, and gets a DHCP-lease from my ISP. Eth1 and eth2 use a static ip-address, and those continue to work. Renewing the DHCP-lease of eth0 works fine by rebooting or by doing it manually, but it doesn't work autmatically like it should. It works fine under Windows2000 or Slackware, but not in Debian, with or without firewall.

If the problem is that your Debian box suddenly loses nameserver information, then installing the resolvconf package (and adding the addresses for dns-nameservers to /etc/network/interfaces) might provide a solution. I haven't used it myself, but other users on this forum have reported that resolvconf can solve some dhcp/dns related problems.
http://packages.debian.org/testing/net/resolvconf

Unfortunatly the problem isn't DNS-related. I tried pinging ip-addresses directly, but that didn't work. Info in /etc/resolv.conf seemed ok to.

Well, that would have been too easy, wouldn't it? ;)

If I was in your position, I'd go through all the config files under /etc that seem to be even remotely networking-related, starting from /etc/network/ and /etc/default/ , trying to figure out what settings make your network connection under Debian behave differently from Windows and Slackware. Here's an overview of setting up net connection on Debian plus introduction to some tools that will help in this task:
http://www.debian.org/doc/manuals/re...ateway.en.html

Of course, it could be also some process that is not networking-related at all but nevertheless interferes with your net connection, but this should show in the log files under /var/log/ and you said you've already went through them finding nothing unusual.

Maybe next time, i already gave up and went back to my old and trusted friend Slackware.

I actually do real work on computers, so i don't have to much time to get things working properly.

But thanks anyway. :)

Your problem is quite unusual but there's no magic involved -- both Debian and Slackware use the same Linux kernel for their networking features. Distros like Debian, Fedora, and Mandrake have some advanced features, like additional hardware detection, and most often these features make them easier to use but sometimes they can interfere and a simple distro like Slackware can come out as the winner. ;) If you actually do real work on computers, as you say, then I suggest that you spend some time learning how to troubleshoot Linux-related problems because you'll meet many other problems using Slackware. But I agree that Slackware is one of the most stable and trouble-free distros out there, so you've made an excellent choice. :)