So I have successfully figured out how to release an IP in Linux finally, dhclient.

I was SSH'd into my server (192.168.0.1) from me (192.168.0.19) and decided to run dhclient to see help, commands etc..

bad idea.

dhclient came up with the stuff and tried to process something which it seemed to get stuck on.

Instantaneously I lost my IRC, ICQ, MSN, the SSH client cut me off, webpages wouldn't load. I lost internet AND lan.

I went to the server and it said:
host 192.168.0.19/if3 ignores redirects from 192.168.0.1 to 192.168.0.1

I didn't know how to fix it so I logged in, shut down the server into maintenance mode, then let it boot back up so the services restarted and I got my net back on my .19 PC, excellent..

But then I woke up the next morning - no net on .19, same message on the server, so I did it again, worked for the whole day till night time where the same thing happened.

I seem to now periodically lose internet and lan on the .19 machine and that night, another machine .18 and I don't know why. So i'm not sure if it's all machines, or just the .19, but for sure atleast the .19. All I did was run dhclient with no parameters when I was ssh'd into the server and I seem to have opened a can of UGLY worms.

I don't know how to fix it - can anyone help?

It looks your dhclients starts from time to time, it couldn't find DHCP server and you have no network access. When you get the same problem, look if dhclinent is running on the server (ps aux|grep dhclinet). If it is, you need to trace the script it's starting from ('cd /etc/rc.d/init.d;fgrep dhclient *' - it will show you places where 'dhclient' is run in the scripts, check every of them).

Note: dhclient doesn't show help. It starts looking for DHCP server...To look into the options, use rather 'man dhclinet'.

Very unclear story. My doubts are:
-what is the server? is it a gateway to internet for LAN clients?
-how many NICs it has got?
-what for you are using dhclient at server box? which NIC(s) it should setup?
-what way the clients IP are setup?
Be more specific....

dorian:

server is a gateway
eth0 24.100.70.86
eth1 192.168.0.1

dhclient is being used on the server to get an IP for my rogers cablemodem.

client IP's are setup as automatic/dynamic/get from server - the dhcp server included in redhat 8.

dhclient is needed for eth0 (address for modem from ISP)
dhcp server looks for lan clients on eth1

using redhat 8 with turtlefirewall (webmin plugin)

Fine. I understand eth0 IP is constant although get via dhclient. You need to setup it to work with eth0 only.
So /etc/dhclient.conf should be for instance:
interface "eth0"{
request subnet-mask, broadcast-address, time-offset, routers, domain-name, domain-name-servers, host-name;
require subnet-mask, domain-name-servers;
}
The most important is to use dhclient on eth0 only.