I'm getting our DR plan up to date after a server upgrade. However, I have realised a small, but very important, point that needs resolving.
Email is our 'business critical' system. I have had a number of things put in place to ensure that this stays up at all times - back/replication, mirrors etc. Our offsite server, aside from holding copies of our backups, also runs mirrors of our DC and our email server. So far so good.
However, we use our DMZ to manage our webmail and Lotus Traveler email traffic. The ip address is attached to our mail.ourdomain.com address. I know we had problems in the past when that particular line went down and we couldn't get traffic to resolve to the address because the IP was no longer there.
In the case where that IP is no longer available (either because the line is down or because I have to use the offsite server), how can I get traffic to go the 'new' ip? How do I configure things so it is just a matter of 'switching' everything over? Does this even make sense??!!