On Thu, 15 Nov 2007, in the Usenet newsgroup comp.os.linux.networking, in article <jwvwssjqhx6.fsf-monnier+comp.os.linux.networking@gnu.org>, Stefan Monnier wrote: >Is there such a thing as a combined DHCP client&server? > >Most of my machines use DHCP to get their IP address and it occurred >to me that when I connect two of them together it would be nice if one >of the two would automatically turn into a DHCP server. That's what 'Link-Local' or 'ZeroConf' is for. 3927 Dynamic Configuration of IPv4 Link-Local Addresses. S. Cheshire, B. Aboba, E. Guttman. May 2005. (Format: TXT=83102 bytes) (Status: PROPOSED STANDARD) >Basically, the client&server daemon would try work as a DHCP client, >trying to connect to some other DHCP server and if that connection >fails, it would start to accept DHCP requests (i.e. keep looking for >some other DHCP server, but as long as none are found be willing to >reply to DHCP queries passing by on the network). The whole idea of ZeroConf is that if there is no DHCP server that will grant an IP, the computer reaches up between it's legs and grabs a random address out of the range 169.254.x.x (there is a functional equivalent for IPv6 in the range FE80::xxxx:xxxx). If you think about it, the client&server has no idea what IPs might be in use. If it's going to allocate addresses out of a routable range (see RFC3330), why not simply configure the thing statically and not worry about grabbing some random address? Old guy