From: Geert Nijs (Geert.Nijs@simac.be)
Date: Thu Apr 17 2008 - 12:35:59 ART
Rik,
Check this. It is actually Option82 insertion that is breaking DHCP when you enable DHCP snooping. There has been previous posts to cciegroup and i myself have also
spend 1 day at debugging the issue.......
If you add the "ip dhcp relay information trusted" on the SVI interfaces that have the IP helper address defined, this
command allows the L3 interface to forward packets that include DHCP Option 82 informations (which DHCP snooping does by default). Without the line, the interface
will not forward dhcp request to the iphelper destination.
On the device doing the forwarding "debug ip dhcp server" will give the error "relay information exists, but giaddr is zero", and the packet will
not be forwarded.
regards,
Geert
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