changing eth0 to default

hi there, ave installed ubuntu 12 server, with 2 NIC cards, choose eth0 to be primary during installation, for squid3 proxy. Nw internet only works with eth1 not eth0 which is the primary. due to this i cant configure the iptables and lan. running sudo nano /etc/network/interfaces
shows

#the primary network interface

auto eth0 inet static
address 81.25.128.x
netmask 255.255.255.x
gateway 81.25.128.x
#dns -xoptions are implemented by the resolvconf package,
dns-nameservers 91.x.x.x 91.x.x.x

iface eth1 inet static
address 81.25.128.x
netmask 255.255.255.x
brodcast 81.25.128.x


any advice?
thanks

 

Did you configure the same IP for eth0 and eth1?

 

it seems that they are swapped...eth1 became the primary

 

http://www.linuxquestions.org/quest.../how-do-i-assign-switch-eth0-and-eth1-308008/