CentOS - Aug 2008 - Outbound connections not using primary eth0 IP

Hello:

I have a machine running CentOS 5.2

I added two IP addresses to eth0 by copying
/etc/sysconfig/network-scripts/ifcfg-eth0
to 
/etc/sysconfig/network-scripts/ifcfg-eth0:0
/etc/sysconfig/network-scripts/ifcfg-eth0:1

and changing the relevant IP info.

I am now seeing outbound connections
failing at my firewall from services like NTP, etc. 
since they are now using a source address
from one of the added IP addresses instead of the
original eth0 IP which is allow through the firewall.

I don't want to have to keep maintaining 3 copies
of each firewall rule to accommodate the new IP 
addresses.

Is there a way to tell the machine to use
the eth0 IP address as the source address for
connections?

Here is the original ifcfg-eth0 file:

# nVidia Corporation MCP55 Ethernet
DEVICE=eth0
BOOTPROTO=none
BROADCAST=206.123.70.63
HWADDR=00:30:48:7A:B4:FE
IPADDR=206.123.70.50
NETMASK=255.255.255.240
NETWORK=206.123.70.48
ONBOOT=yes
GATEWAY=206.123.70.49
TYPE=Ethernet

Here is ifcfg-eth0:0
# nVidia Corporation MCP55 Ethernet
DEVICE=eth0:0
BOOTPROTO=none
BROADCAST=72.249.130.47
HWADDR=00:30:48:7A:B4:FE
IPADDR=72.249.130.42
NETMASK=255.255.255.248
NETWORK=72.249.130.40
ONBOOT=yes
GATEWAY=72.249.130.41
TYPE=Ethernet

Here is ifcfg-eth0:1
# nVidia Corporation MCP55 Ethernet
DEVICE=eth0:0
BOOTPROTO=none
BROADCAST=72.249.130.47
HWADDR=00:30:48:7A:B4:FE
IPADDR=72.249.130.43
NETMASK=255.255.255.248
NETWORK=72.249.130.40
ONBOOT=yes
GATEWAY=72.249.130.41
TYPE=Ethernet

Any ideas why this is happening?

Thanks,
  Neil

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Neil Aggarwal, (832)245-7314, www.JAMMConsulting.com
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On Mon, Aug 4, 2008 at 13:00, Neil Aggarwal <neil at jammconsulting.com>
wrote:
> Any ideas why this is happening?
Because you have two different default gateways. In that case, Linux
will "rotate" between them, using one or the other for each outgoing
packet.

If you want all your outgoing traffic to go through one gateway only
(from what you write, that is probably what you want), only remove the
GATEWAY= line from the :0 and :1 files and restart the network with
"service network restart".

HTH,
Filipe

Neil Aggarwal wrote:
> Any ideas why this is happening?
Try looking at this?
http://www.clintoneast.com/articles/multihomed.php

In general I try to make sure my systems only have 1 default
gateway, makes life a lot easier. Leave the multi homing to
the routers(or my preference layer 3 switches).

nate