D'Arcy J.M. Cain wrote:

Right. One side needs to change a config file in their DHCP server and maybe their internal DNS. If they need to change much more than that then its time for a network re-engineering anyway.

That, IME, is the real issue here. The re/engineering that should be part of an M&A is too often under-budgeted. There is not enough staff, time, or budget to do the needful as it were. Same thing occurs across IT. In most cases we see it as deferred maintenance. Hardware and software upgrades, routing updates, security, etc. are all a hard sell when the network is working fine and some other department can better demonstrate a need for budget. In all of these cases IT management needs to make the case, submit the CYAs, and let C-levels take it from there. Be glad you're a network engineer. Deferred maintenance is much more of a problem on the systems administration side of IT. One of the largest ISPs I know has state of the art networks but its server farms are running an OS that has been out of support for years. One of the largest schools I know ran their entire email infrastructure on hardware that hadn't been upgradable for years... all with predictable results. Roger Marquis