I would like to know if this is possible with my existing equipment. I will have two different ISP's, each supplying me with a respective public IP address. I will have a Cisco ASA5520 handling both ISP's. The ASA will be attached to a Cisco 3750 running the EMI IOS image. My web server will be attached to the 3750. What I would like to happen is for the web server to be accessible from either of the public IP addresses at any time. For example, let's say www.domain.com
resolves to 192.168.1.1 (ISP1) and backup.domain.com resolves to 192.168.2.1 (ISP2). At this point in time the web server is going to send all it's traffic back out the default gateway (192.168.1.1), so if an end user tries to access it via 192.168.2.1 they will get no response. Is there a way to somehow 'tag' the packets maybe using CoS or DSCP and then use Policy Based Routing on the 3750 to send the traffic back out the interface from whence it came? Just need a kick in the right direction here..