[CentOS] Routing issue - Revisited

Wed Jul 22 06:10:46 UTC 2009
Doug Coats <dcoatshca at gmail.com>

A number of weeks ago I had huge help from many of you configuring routing
on a server with multiple Internet facing nics.  Thanks for all of your
help!!!!

I am still having a routing issue that I am hoping someone can help me
tweek.  This server, besides acting as our gateway to the internet, is also
our web and email server.  The server has 4 nics.  Two are connected to the
internet and the other two route traffic to internal subnets.

Our network topography in question looks like this:

Internet - Gateway Server - 192.168.4 subnet - Internal Server - 192.168.6
subnet - Clients

The problem that I am experiencing is that part of our internal network, the
192.168.6 subnet cannot view our website that is hosted on our Gateway
server.  Our Internal Server can access the site but the Clients simply time
out looking for it.

If I point the Client to the internal address of the Gateway Server I can
pull up the site but if I use the URL the browser times out.

If I turn off my ip rules I can then view the URL on my Clients but of
course external routing falls apart.

/etc/sysconfig/network-scripts/rule-eth2

from 173.11.51.45 table Cable
/etc/sysconfig/network-scripts/rule-eth3

from 67.152.166.2 table T1
/etc/sysconfig/network-scripts/route-eth0

GATEWAY1=192.168.4.3
NETMASK1=255.255.255.0
ADDRESS1=192.168.6.0
GATEWAY0=192.168.4.2
NETMASK0=255.255.255.0
ADDRESS0=192.168.5.0
/etc/sysconfig/network-scripts/route-eth1

GATEWAY0=192.168.4.1
NETMASK0=255.255.255.0
ADDRESS0=192.168.4.0

/etc/sysconfig/network-scripts/route-eth2

173.11.51.44/30 dev eth2 proto kernel scope link src 173.11.51.45 table
Cable
173.11.51.44/30 dev eth2 src 173.11.51.45
default via 173.11.51.46 table Cable
default via 173.11.51.46
192.168.4.0/24 dev eth0 proto kernel scope link src 192.168.4.1 table Cable
/etc/sysconfig/network-scripts/route-eth3

67.152.166.0/27 dev eth3 proto kernel scope link src 67.152.166.2 table T1
67.152.166.0/27 dev eth3 src 67.152.166.2
default via 67.152.166.1 table T1
192.168.4.0/24 dev eth0 proto kernel scope link src 192.168.4.1 table T1
# ip rule list
0:      from all lookup 255
32764:  from 67.152.166.2 lookup T1
32765:  from 173.11.51.45 lookup Cable
32766:  from all lookup main
32767:  from all lookup default
# ip route show
173.11.51.44/30 dev eth2  scope link  src 173.11.51.45
67.152.166.0/27 dev eth3  proto kernel  scope link  src 67.152.166.2
192.168.6.0/24 via 192.168.4.3 dev eth0
192.168.5.0/24 via 192.168.4.2 dev eth0
192.168.4.0/24 dev eth0  proto kernel  scope link  src 192.168.4.1
192.168.1.0/24 dev eth1  proto kernel  scope link  src 192.168.1.1
169.254.0.0/16 dev eth3  scope link
default via 173.11.51.46 dev eth2
# ip route show table cable
173.11.51.44/30 dev eth2  proto kernel  scope link  src 173.11.51.45
192.168.4.0/24 dev eth0  proto kernel  scope link  src 192.168.4.1
default via 173.11.51.46 dev eth2
# ip route show tabel T1
67.152.166.0/27 dev eth3  proto kernel  scope link  src 67.152.166.2
192.168.4.0/24 dev eth0  proto kernel  scope link  src 192.168.4.1
default via 67.152.166.1 dev eth3
Any insight would be greatly appreciated!  I have been pecking away at it
and I just can't seem to get it right.

Thanks - Doug
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