Linux static rotue problem.

[Siliconjunkie]

I have a Redhat 8 box that has an odd static route problem. It has 2 interfaces, eth0 and eth1. eth0 faces the internet and should be the default route, eth1 points towards the private network.

Now for some reason it keeps putting the default gateway on eth1. We are using /etc/sysconfig/networking/devices/eth1.route which is called by the interface init script /etc/sysconfig/network-scripts/ifup . The eth1.route file does not contain a default route. The eth0.route file contains ONLY a default route. All of that looks fine. When I grep for 0.0.0.0 recursively from /etc it doesnt appear anywhere it shouldnt. So, everything looks like it should be fine.

When it comes up it has the wrong default gateway and its on eth1. So, I have hunted and hunted for where it could be getting this gateway from. It is a valid gateway, so I am assuming it is something leftover and I cannot locate it. I have grepped and grepped with no luck.

So, any ideas where it may be getting this from?

[Siliconjunkie]

Ok, I figured it out.

In my troubleshooting/poking around I noticed when I did a restart on the network It brought down/up eth0, eth1, eth1old, eth2. Weird part was that eth1old did not show up in an ifconfig. So, I looked in /etc/sysconfig/network-scripts/ where it keeps the config for each interface. In the eth1old config the incorrect gateway was setup. I moved the file ifcfg-eth1old to another dir and restarted the network. Only the correct interfaces came up and it had the correct gateway.

What was happening is when the network came up, it would set it properly when it brought up eth0, eth1 came up with no problems, eth1old came up and overwrote the gateway.

The fact that eth1old was not showing up in ifconfig it kept me from going that direction. Once I narrowed this down it was easy.