Moving Mail Server to another location / IP address?

[listreader at pvision.co.uk]

>I need to move a machine running MacOSX Server 10.4.8, particularly 
>mail services but also some Web sites to another location and IP 
>address....

If you're beholden to an ISP for any DNS changes I'd make them on a Tuesday or Wednesday so that you can chase them in 48 hours if things go pear-shaped. I've done changes on a Friday before now and the ISP has got the changes wrong. If that happens you have to wait 48 hours to contact the ISP (Saturday, Sunday) and then wait another 48 for the changes to propagate

I'd also make the hardware changes at another time so you're making the minimum number of changes at one time. Easier to fault-find that way