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Cisco Bug: CSCtc84781 - DHCP snooping w/ option82 :release message gettin faked after reload

Last Modified

May 25, 2010

Products (1)

  • Cisco IOS

Known Affected Releases


Description (partial)

Console messgae :"DHCP_SNOOPING: binding interface mismatch, drop faked dhcp message 

DHCPRELEASE and no binding update."  is seen on 7600 box acting as a DHCP Relay and Configured for Snooping, when DHCP client sends a Release message after Router reload.

DHCP snooping w/option 82 over EVC PC.

1) bring up a dhcp snooping binding with a huge lease time ( say 1 day)
2) Make sure dhcp snpooping database is configured.
3) Copy a new SRE image to the router.
4) Reload the box with this image.
5) When the box comes up, make sure the binding is still present.
6) Enable snooping debugs, Release the binding from STC.
7) Snooping recognizes this as a fake message and drops it.
8) Binding is not released :
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