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Cisco Bug: CSCtb36561 - After ISSU, relay policy on SVIs w/o helper add. is not removed on own

Last Modified

Feb 05, 2017

Products (1)

  • Cisco Nexus 7000 Series Switches

Known Affected Releases


Description (partial)


After ISSU, VACL redirect entries for DHCP ACL  will not be removed on SVIs without helper 
addresses configured, and for cases with helper address configured the cleanup of the
 VACLs does not happen correctly. Due to this, some of the non-dhcp packets like PXE boot 
packets trapped by Nexus SUP may not be forwarded appropriately.


1.  Enable DHCP relay (using `service dhcp`) and configure SVI(s) with/without relay helper 
address. Do ISSU to 4.2.1 image.  This results into issue.


1. After ISSU, add a dummy helper address (using `ip dhcp relay address x.x.x.x`) and then 
remove it (using `no ip dhcp relay address x.x.x.x`) on  all SVI interfaces (  where helper address
 is not  intended to be configured).

Note: Please review the Release-notes of CSCsy13155 to apply refined ACL fix for all the 
interfaces where relay helper address is configured.

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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
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