> How would you go about building a fault tolerant solution so that both ISPs > can be used (either load-shared or as active/backup) for outbound client > traffic and inbound SMTP traffic?
This can be accomplished using BGP on your routers. In order for this to work, you will need the cooperation of your ISPs, because they will need to work together with you a bit to get it to work. You will also need to go to www.arin.net and get an ASN ($500 + $30 a year). If you talk to your ISPs they should be able to give you a great deal of help with the specifics of this process, or any the Cisco IP Routing books covers this well. As fas as getting PIX to do this, I am not a Cisco expert so I am not sure, but I have a hard time imaging that they would not. I am in the process of doing pretty much the exact same thing (on a 3640), and have gotten a lot of cooperation from my ISPs on it. Stephen Kemler
