Having done this a time or two, there are some things that can help you.
1) Do what HE said. Have a plan and stick to it. It's important that
you also know when to blow off a step if it is getting to costly.
2) Multi-address everything you can. Our server boxes are all capable
of multiple IP addresses, so we add new IP aliases for them before we
change. This gives us the flexibility and opportunity to test some of
the changes ahead of time (*NOTE* be sure to tell your router to block
that Class "C" before you start and MAKE SURE you tell it to pass the
addresses once you've switched).
3) Your Nameserver entries will probably be the most problematic. If
you can, establish a separate machine to build your new nameserver
addresses on so that you can drop that onto the new LAN first. While I
despise the use of names during testing, there are still times when the
name of a machine is going to be important (think _sales_ or _marketing_
people).
4) Plan to be down for the entire upgrade period. Bring up your
dial-in stuff LAST in the plan. While your dial-in customers (internal
or external, doesn't matter) may not like it, they would be less happy
about their favorite X-rated newsgroup not being available....
-- Dave Burgess Network Engineer - Nebraska On-Ramp, Inc. *bsd FAQ Maintainer / SysAdmin for the NetBSD system in my spare bedroom "Just because something is stupid doesn't mean there isn't someone that doesn't want to do it...." - To unsubscribe, email 'majordomo@livingston.com' with 'unsubscribe portmaster-users' in the body of the message.