Updated at the bottom
I'm using Centos as a router, and just replaced the routing system at work. I've got 2 routers to send data around. For the most part it's working. On one router I have 2 network ranges that are on the same nic (eth1). We have a server on one range, and anyone in the other cannot SSH to it. But, it can be pinged.
Here's a quick layout:
eth0 - 192.168.144.50 (link between routers) eth1 - 10.10.10.254 - 255.255.254.0 (10.10.10.x and 10.10.11.x ranges) eth2 - internet
eth0 - 192.168.144.24 (link between routers) eth1 - 18.104.22.168 & 10.98.0.1 ranges (yes, I know 22.214.171.124 is not for private use, this is a legacy setup that we haven't been able to remove yet)
Here is the ip route printout:
126.96.36.199/24 dev eth1 proto kernel scope link src 188.8.131.52 192.168.144.0/24 dev eth0 proto kernel scope link src 192.168.144.24 10.98.0.0/24 dev eth1 proto kernel scope link src 10.98.0.1 default via 192.168.144.50 dev eth0
The server is on 184.108.40.206. I have a laptop running on 10.98.0.165. I get a response from the command: ping 220.127.116.11. But, when I try to ssh to it, I get nothing. Through doing some tcpdump commands on my routers, I'm seeing that the packets for the ssh command are going from the laptop, to the internet router (192.168.144.50) and back to the correct router.
My iptables list is empty. You can see my ip route output above. Any ideas? I've been staring at this all day. The way I understand it, is that the router should send the packet back through eth1 for 18.104.22.168 to pick up. Thanks.
Edit: Scratched out the bouncing part. I realized that I was seeing ssh traffic from my ssh session into the router, and attributed it to my ssh request.
Update I separated my setup. Now 98.0.0.x is on eth1 and 10.98.0.x is on eth2. What I'm seeing isn't making much sense though.
When I ping the 22.214.171.124 server from my 10.98.0.165 laptop, I get a reply. The route it is taking is odd. It goes through the default route to 192.168.144.50 (internet router) and back through to 126.96.36.199. (tcpdump on eth0 of the internet router found this)
One tidbit. When I started the project, I was trying to do policy routing to make 2 internet providers work. Is there something related that could be doing this?
Here's my updated layout for the second router
eth0 - 192.168.144.24 (router link) eth1 - 188.8.131.52 / 24 eth2 - 10.98.0.1 /24
and ip route show
184.108.40.206/24 dev eth1 proto kernel scope link src 220.127.116.11 192.168.144.0/24 dev eth0 proto kernel scope link src 192.168.144.24 10.98.0.0/24 dev eth2 proto kernel scope link src 10.98.0.1 default via 192.168.144.50 dev eth0