Dual WAN 1600

[Foxy]

I will be running 2 x ISDN links (to two different Internet ISPs) through a Cisco 1600 with 2 WAN cards. I want to be able to have 'failover' between these 2 WAN links so if one link fails, traffic can still get through on the other link.<br>
<br>
This seems pretty straightforward for outbound traffic--I assume the router can be configured to select an active link to send out on. How can I arrange things so that _inbound_ traffic, particularly to my mailserver machine, can find its way in over one or other of my ISDN links, regardless if one link happens to have failed at any moment?<br>
<br>
Will this require border gateway patrol? Are there issues to be aware of in setting this up?

 

[EG]

Are you using your own IP address space? Will both links be "nailed up"?

 

[Foxy]

I currently have a C-class address space leased from ISP #1. This IP addresses from this C-class are used within our LAN environment. I will lease other IP addresses from ISP #2 to support a colocated web server installation at their premises.<br>
<br>
I want the second ISDN link to our LAN to function as a 'transit' link to our colocation providers. This will provide direct connectivity to our colocated server, and provide a secondary redundant internet linik when required.