I have two networks on a server.  One being my internal network, and the other being an external IP address.  This is on Debian Lenny.  Here is my /etc/network/interfaces file:# This file describes the network interfaces available on your system# and how to activate them. For more information, see interfaces(5).# The loopback network interfaceauto loiface lo inet loopback# The primary network interfaceauto eth0iface eth0 inet static        address 172.16.130.250        netmask 255.255.255.0        broadcast 172.16.120.255        gateway 172.16.130.1auto eth1iface eth1 inet static        address 24.249.hidden ipaddy        netmask 255.255.255.224        broadcast 24.249.hidden broadcast.255        gateway 24.249.hidden gatewayI can reboot my system and sometimes eth1 is accessible from SSH, and other times eth0 is accessible.  Then sometimes eth1 will just stop being pingable alltogether.  This is a fairly fresh install of Debian, and the only thing I have running is VMWare Server 2.0, bridged to both of my network connections.
Two networks cannot be accessed simultaneously
linux;debian;networking;routing;vmware
You've defined a gateway on both interfaces. So there is a default route through both interfaces. I'm not sure what exactly happens in this case, but I doubt this is what you intended. I suspect that only a smaller network should be accessible through eth0. You can do this by changing the corresponding stanza like this:iface eth0 inet static    address 172.16.130.250    netmask 255.255.255.0    broadcast 172.16.120.255    up route add -net 172.16.120.0/20 gw 172.16.130.1 eth0