[ale] TCP/IP routing on RHEL3 ES

[Ryan Fish]

There are no gateways specified in the ifcfg-ethX files so there shouldn't
be any confusion on that part.

 

I'm not sure why just restarting the network service isn't accepting the
changes and going about its business as I believe it should but I had to do
the following:

 

1) route del default gw 192.168.3.1 (I had added this manually)

2) set the gateway to 209.168.x.x in /etc/sysconfig/network

3) reboot

 

When the box came back up everything was how it should be and IP traffic was
routed properly again.

 

Any ideas why the reboot was necessary to get this to work right???

 

Thank you.

-Ryan

 

  _____  

From: Jerry Yu [mailto:jjj863 at gmail.com] 
To: ale at ale.org
Sent: Tuesday, January 31, 2006 2:54 PM
To: FishR at bellsouth.net; Atlanta Linux Enthusiasts
Subject: Re: [ale] TCP/IP routing on RHEL3 ES

 

you may want to check ifcfg-eth? to see whether they have GATEWAY=
specified. I've seen 'network' init script got confused (from where I stand)
about which gw to use as default route, when GATEWAY= is speficied in
multiple ifcfg-eth? files.

On 1/31/06, Ryan Fish <FishR at bellsouth.net> wrote:

I recently had to move a public IP address from one web server to another in
the same farm.  Upon doing this I have experienced routing issues that I've
been able to "fix" by manually adding the correct default gateways on each
box.  However, these entries will not remain in place after a reboot (as per
normal) but I am unable to get traffic to route properly on either box if I
add the proper gateway information to /etc/sysconfig/network.

Box A

Now only on 192.168.3.X network, Class C, GW 192.168.3.1

Formerly on 209.168.X.X network, Class C, GW 209.168.X.X

Without using "route add default gw 192.168.3.1 eth0" no GW is shown in the
routing table however the traffic does appear to route properly.  Why?

Unfortunately I have lost access to this box at this time as I made a change
(set GW to 192.168.3.1 in /etc/sysconfig/network) and restarted the network
(service network restart).  I will have to head out to the DC to change
things back soon.

----------------------------------------------------------------------------
--------------------

Box B

192.168.3.X network, Class C

Now also has 209.168.X.X, Class C, GW 209.168.X.X

 I had to manually to do the following to get this box to route right after
moving the public IP to it:

 ip route del default via 192.168.3.1 dev eth0

route add default gw 209.168.X.X eth1

 /etc/sysconfig/network still shows 192.168.3.1  <http://192.168.3.1> as the
gateway

 What am I missing and/or doing wrong here?  I've re-IP'd these boxes before
without this type of trouble.  My online searches haven't come up with much
useful info either.

 Hopefully what I just typed above makes some sort of sense.

 Thank you in advance!

 -Ryan 

 

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