At 10:01 AM 6/26/02, [EMAIL PROTECTED] wrote: >Yes. The DHCP packet will be sent out with the source address of the router >in the unicast packet.
A router had many IP addresses, however. To make your statement less ambiguous, it's important to state that the router uses the address associated with the interface that the DHCP request came in on. For example, consider a router that has an Ethernet 0 interface that connects a LAN with DHCP clients on it. Let's say that the LAN is subnet 10.10.10.0/24 and the router's IP address on that LAN (on e0) is 10.10.10.1. There's no DHCP server on the LAN. So on e0, you configure an IP helper address to reach the DHCP server whose address is 172.16.0.2. Let's say network 172.16.0.0/16 is out the router's e1 interface and that the router's IP address on that interface is 172.16.0.1. The router converts the DHCP broadcast coming in on e0 to a unicast and uses 10.10.10.1 as the IP source address. The router sends this unicast out e1. The router also puts the 10.10.10.1 IP address in the GIADDR field in the DHCP request. In fact, that's actually what the DHCP server looks at. I don't think the DHCP RFC requires the server to look at the source IP address. The RFC does say, however, that a BOOTP Relay Agent must put its IP address in the GIADDR field. The relay agent must fill this field with the IP address of the interface on which the request was received. That's how the server knows which scope to use. Priscilla >Eric Lange > > > > > > >dimitri@ptsci > nti.com To: >[EMAIL PROTECTED] > Sent by: >cc: > nobody@groups Subject: DHCP question >[7:47477] > >tudy.com > > > > > >06/26/2002 > 08:39 >AM > >Please > respond >to > >dimitri > > > > > > > > >Let's assume a Win2k DHCP server is set up correctly with different IP >scopes for 2 remote sites. Let's also assume remote-site routers are >set-up correctly with the correct IP helper-address. When remote DHCP >clients start broadcasting for IP addresses at each remote site, and >these broadcasts are then forwarded by the remote-site routers as >unicast packets to the DHCP server, how does the DHCP server know from >which scope of IP address to full-fill a DHCP client request for a given >remote site. Is the information embbeded within the DHCP packet itself? > >thanks >dj ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47533&t=47477 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
