On Thu, 23 Jun 2005, Josh Welch wrote: > So I'm trying to cut over a network from one provider to another. This > also means cutting over from one chunk of IP's to another because we > don't have our own allocation. I was hoping I could do something cute > like putting in a second NIC, assigning that nic an IP on the new > network and that host would anser requests from both networks during the > cutover, packets which come in on eth0 go out on eth0, packets which > come in on eth1 go out eth1. Sounds simple, eh? What is this host doing, firewall or NAT, or just a router? > This does not, however, seem to be the case. It seems to want to pick > one interface and use that for outgoing traffic. Is this the way it > should be? Can I convince it to behave like I want it to? It's probably sending out using whatever interface has the default route. By far the easiest way to switch over is to just change your default to the gateway IP of the new provider, and have all traffic go out that connection. You'll still get traffic coming in through your old provider, you'll just be sending ALL outgoing packets back out the other direction. This will work as long as your new provider isn't doing anti-spoofing filtering for outbound traffic (many, unfortunately, do not).