[CentOS] Multiple network cards - routing issue?

Sat Jul 18 17:41:53 UTC 2015
Frank Cox <theatre at melvilletheatre.com>

I have a Centos 5 machine here that, up until about a year ago, was happily running Icecast and serving streaming audio through through three network connections, consisting of one "local" connection (local address 192.168.1.5)  and two cable modems to talk to the outside world.

We shut this down about a year ago, but now I am attempting to get it going again on one outside connection instead of two.  Simply changing the IP address on one of the network cards to use the new address isn't working, so the notes that I made when I set this thing up in the first place must be incomplete since I'm obviously missing something here.

I have two "active" IP addresses that I want to use at the moment.

 eth0 is 192.168.1.5 and is working fine.  I can log into the server with ssh and run icecast and listen to streaming audio just fine.

eth1 is now supposed to be 204.83.105.1 so I configured the new address on that card with system-config-network.

The third card (eth2) I plan to ignore for the time being so I haven't changed that or done anything with it at all.

My /etc/iproute2/rt_tables looks like this.  I haven't changed it from what it was when I originally set this thing up a few years ago.

#
# reserved values
#
255     local
254     main
253     default
0       unspec
#
# local
#
#1      inr.ruhep
50      access1
60      access2

Note the access1 and access2 entries at the bottom of the file.

I then ran the following three commands:

ip route add 204.83.15.0/24 dev eth1 table access1
ip route add default via 204.83.15.254 dev eth1 table access1
ip rule add from 204.83.15.1/32 lookup access1

These are the same commands that I used to set up the previous Internet connection on this server -- The only thing that I have changed was the IP addresses.

Here is the output from "ip route show":

[root at audio ~]# ip route show
192.168.1.0/24 dev eth0  proto kernel  scope link  src 192.168.1.5 
204.83.15.0/24 dev eth1  proto kernel  scope link  src 204.83.15.1 
169.254.0.0/16 dev eth1  scope link 
default via 204.83.15.254 dev eth1 

That seems to indicate that the default route is 204.83.15.254 which is the correct gateway number for that Internet connection.

However, a ping or traceroute command (ping google.com or whatever) gives me no output.

I've missed a step somewhere.

I hooked my laptop up to that Internet connection to insure that the modem and whatnot is working and it is, so there's obviously something wrong with my configuration.

Can any of you folks tell me what I've missed?

-- 
MELVILLE THEATRE ~ Real D 3D Digital Cinema ~ www.melvilletheatre.com