WHen the DHCP packet is forwarded, the DHCP relay agent will insert the primary IP address of the interface the packet was received on into the DHCP packet's giaddr field.
When adding secondaries to an interface where you're doing DHCP, make sure: - routing to the primaries and secondaries is in place and the DHCP server(s) can reach these IPs - the provisioning system is configured to relate all secondary scopes back to the primary scope. "Waters, Kristina" wrote: > > Everyone, > > I'm in the process of changing my internal IP addresses and ran into a > problem on the first site I went to swap. Clients obtain their ip from a > dhcp server at my location, so I added a secondary ip address to the remote > router as shown below: > > interface Ethernet0 > ip address 172.16.x.x 255.255.255.128 > ip address 10.x.x.x 255.255.255.0 secondary > ip helper-address 172.16.x.x > > Got everything else set up, yet no one was obtaining IP addresses. I > flip-flopped the addresses and made the old 172.x.x.x address the secondary, > the 10.x.x.x address the primary and everything started working fine. > > Does ip helper only work with primary address on the interface? This > particular router had an older version of code, 11.1. > > Just curious, > > Kristina L. Waters > LAN/WAN Engineer > www.absfirst.com > > "Many of life's failures are people who did not realize how close they were > to success when they gave up." > Thomas A. Edison > > ********************************************************************** > This email and any files transmitted with it are confidential and > intended solely for the use of the individual or entity to whom they > are addressed. If you have received this email in error please notify > the sender by email, delete and destroy this message and its > attachments. > ********************************************************************** Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=61621&t=61607 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
