Send mail through separate internet connection

By "in parallel with the firewall" are you saying you're bypassing the firewall?

An obvious question is why? What difference does it make which way it goes out?

Your MX records have absolutely nothing to do with your outgoing e-mail.

When they do mail pushes the internet slows down or stops so using the dsl connection out for mail would fix that problem a 2nd mx record would allow me to also recieve mail through the dsl connection when the t1 is inaccessable

I don't have a full picture of your network but you may be able to do what you want with policy based routing.

You could match tcp port 25 traffic and send it in a particular direction leaving the other traffic to be routed normally.

To me, policy based routing seems to be the answer as well. In order to do Policy based routing, you would need to have the traffic flow through the router that will make the decision on which path to forward on. This means you will need to change the topology of your network. This is how I understand your current setup: (view in mono-spaced font)

__________ ________ | | | (T1) / \\ ______________ |---| Firewall |---------( ) / \\ | |__________| \\ / / inside network \\___| / \\ \\ 10.100.10.0/24 / | ( internet ) \\______________/ | ____________ \\ / | | | (DSL) / \\ |--| DSL Router |--------( ) | |____________| \\________/

If you change the topology to the following (again mono-spaced font) you will be able to implement the PBR.

______________ | / \\ | __________ / inside network \\___| | | | ________ __________ \\ 10.100.10.0/24 / |---| Firewall |---| | | (T1) / \\ \\______________/ | |__________| |---| Router |-------- ( ) | |________| \\ / | | internet | | (DSL) / \\ |------------ ( ) \\__________/

However, the sheer fact you've asked the question leads me to believe you will need much more help on implementing the PBR than what we (the internet community) can provide here.

Good Luck. JC