Vic Cross writes: > On 01.05.2002 at 23:13:41, Rich Smrcina <[EMAIL PROTECTED]> wrote: > > > If I'm hearing your question correctly, you mean outside of the Guest Lan, > > right? Great question... > > Ummm... Sorry Rich, can't take credit for that! I was simply talking about > inside the Guest LAN. You're right, it's a great question! ;-) > > Issues of propagating broadcasts across networks are many and varied, as David > replied earlier. In the DHCP scenario, though, there's a configuration that my > Cisco friends call "DHCP helper", that allows (as I understand it) a router to > pick up a DHCP request from a subnetwork and unicast it to a DHCP server on > another network. This gives you support for centralised DHCP (one site I know > of uses this to provide DHCP to thousands of PC across the country using DHCP on > z/OS).
The helper is called a relay: RFC2131 specifies that DHCP must be able to use the same relay system as defined for BOOTP in RFC951. The DHCP suite (the ISC server-side one, not the client-side dhcpcd) which comes with Red Hat (RPM name dhcp) comes with such a relay (called dhcrelay). Other distributions probably do too. Invoking it as "dhcrelay -i ifname server0 server1..." listens for request broadcasts on interface ifname and then unicasts them to the real DHCP servers server0... . When it receives a reply, it broadcasts it back to the initial requester. --Malcolm -- Malcolm Beattie <[EMAIL PROTECTED]> Linux Technical Consultant IBM EMEA Enterprise Server Group... ...from home, speaking only for myself
