Ubuntu – Set default outgoing IP on Ubuntu server with multiple IPs

networkingUbuntu

I have a server (10.04 LTS) with 1 NIC and 2 virtual IPs. My /etc/interfaces is:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
  address 11.22.176.5
  network 11.22.176.0
  netmask 255.255.255.192
  broadcast 11.22.176.63
  gateway 11.22.176.1

auto eth0:0
iface eth0:0 inet static
  address 11.22.178.30
  network 11.22.178.0
  netmask 255.255.255.128
  broadcast 11.22.178.127
  gateway 11.22.178.1

auto eth0:1
iface eth0:1 inet static
  address 11.22.178.36
  network 11.22.178.0
  netmask 255.255.255.128
  broadcast 11.22.178.127
  gateway 11.22.178.1

I have a web script that reports what IP it sees. So:

"curl --interface eth0:0 http://server/reportIP" correctly reports "11.22.178.30"
"curl --interface eth1:1 http://server/reportIP" correctly reports "11.22.178.36"

However

"curl http://server/reportIP" reports a random IP (from the 3 total IPs) while I want to always see the main IP (11.22.176.5).

So how can I force the use of the default IP unless I specifically go through a virtual interface?

Edit: result of route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
11.22.176.0     0.0.0.0         255.255.255.192 U     0      0        0 eth0
11.22.178.0     0.0.0.0         255.255.255.128 U     0      0        0 eth0
0.0.0.0         11.22.176.1     0.0.0.0         UG    0      0        0 eth0
0.0.0.0         11.22.178.1     0.0.0.0         UG    100    0        0 eth0
0.0.0.0         11.22.178.1     0.0.0.0         UG    100    0        0 eth0
0.0.0.0         11.22.178.1     0.0.0.0         UG    100    0        0 eth0

Best Answer

I'm not sure how it works with multiple subinterfaces, but try the below:

In /etc/networking/interfaces, add, replacing eth0:1 with the desired subinterface:

up route add -net 0.0.0.0/0 gw 11.22.178.1 dev eth0:1
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