Ok, I am working this problem backwards. I have actually fixed it, but I am not sure what went wrong. In the interest of the learning process, I am hoping someone can explain it.

Last night I loaded Ubuntu Server on a PC I have. It's version 6.06 of the server. I loaded the server, then assigned a static IP address via the "interfaces" file. I then brought eth0 down and back up. All went well. It had the new static IP.

Around 5 minutes later, I couldn't SSH into the box. I looked, and it had set its IP back to a DHCP assigned address from my router. After checking all the settings and verifying, I decided to reboot the server.

Upon rebooting, all has been fine ever since. The interfaces file had not changed, and is still the same.

Any ideas why it kept using a DHCP address, even after it was initially working with the static IP address?

Thanks!

Is it possible that dhclient was still running in the background to get IP addresses?

It's possible. The initial setup did not give the option of configuring the network card during the install, so it just grabbed an address from my router. I would have thought assigning a static IP, then cycling the interface would have stopped any IP address seeking but I am not sure.

I have dabbled with Linux for years, but have never dug deep into the processes and so forth. I am hoping to get that experience with this server.

Thanks for the reply! That gives me something to look into.

dhclient is a runs as a process in the background, so simply doing if-down/if-up on the interface isn't going to stop it from running. It's not the interface itself that is looking for a DHCP lease, there's a program that's sending DHCP discovery requests across the network and happens to assign those values to the interface if it discovers them.

Chort is entirely correct. Usually one of the first steps I take when building a debian server with static IP is Then your static address will stick, instead of dropping back to a dhcp address.

Peace,
JimBass

Thanks chort. So when I changed the interfaces file and specified static instead of DHCP, I should have killed the dhclient process as well it appears.

I assume the static line in the interfaces file told the system that dhclient wasn't needed upon reboot then?

Thanks again!


edit: Thanks Jim! One final question above... on the interfaces file. The static notation in the interfaces file is what told the server not to start the process seeking a DHCP address I assume? After the reboot it ran fine, and I obviously didn't do anything with the DHCP process as I didn't know it existed. The only thing I changed was the interfaces file.

That's correct.