Path: utzoo!attcan!uunet!convex!killer!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!ames!pasteur!ucbvax!NNSC.NSF.NET!craig From: craig@NNSC.NSF.NET (Craig Partridge) Newsgroups: comp.protocols.tcp-ip Subject: re: Dynamic IP address assignment Message-ID: <8811240047.AA28910@ucbvax.Berkeley.EDU> Date: 23 Nov 88 16:19:46 GMT Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 24 > In article lear@NET.BIO.NET (Eliot Lear) writes: > >Wouldn't you run into a problem with ARP caches if you dynamically > >assign internet addresses to ethernet based machines? > > Age the arp cache. Then set a "re-use" timer on the IP > address to be, say 3x, the arp cache time-out. > Of course, how do you know when an IP address is released? > There oughta be a protocol. A protocol won't help with the release of IP addresses -- what happens if the machine goes down, or its owner disconnects his portable PC and walks away, before the machine gets a chance to release its address? I think any system one develops for reclaiming addresses has to assume the system might silently go away. Note that this is one reason why I feel that there is a difference between transient assignment (IP addresses dynamically assigned for short term use, and thus addresses that must be reclaimed) and one-time configuration assignment (unpack the box and have it learn its IP address once and for all -- you may want to reclaim addresses once every few years, but that can probably be done by hand). Craig