changing DHCP server's IP address

changing DHCP server's IP address

Post by Brian Purcel » Fri, 05 Mar 1999 04:00:00




> Are there any strange side effects when changing a DHCP server's IP address?
> I know the lease renewal relies on broadcasts, but I don't know if the
> renewing client needs to rely on a specific IP.  Any help is appreciated!

Actually, the renewal is unicast based at first.  The renewing client will
attempt to renew its lease with the server that issued it by sending a request
to the IP address of that server.  This starts when the lease is 50% of the way
to its expiration.  If it can't find the server, it will try again at regular
intervals until 87.5% of its lease has expired.  *Then* it will start
broadcasting to find any DHCP server that can renew it's lease.  At that point,
it should find your newly addressed DHCP server.

Aside from a little extra traffic while your clients go through the 50-87.5%
phase, there should not be any problems, especially if your users restart their
workstations daily.

--Brian Purcell, MCSE, MCP+I
Local Area Network Manager
Office of Educational Resources
University of Texas Health Science Center at San Antonio