nexus 5K DHCP issue

[bala020881]

I'm experiencing issue with DHCP on Nexus 5K. I have ip dhcp relay address defined on the SVI (Vlan 10). In addition to that I have few another DHCP servers on the same broadcast domain.

interface Vlan 10
  no shutdown
  vrf member CUSTA
  ip address 172.106.133.1/21
  ip dhcp relay address 172.106.145.100
  ip dhcp relay address 172.106.145.101

other DHCP servers 

DHCP server 172.106.128.62
DHCP server 172.106.128.63

Issue: when the ip dhcp relay address is specified in the SVI. other DHCP servers in the same broadcast domain is not getting the DHCP request.

[Reza Sharifi]

Does this happen when you add the VRF to the SVI?

To test, you can remove the "vrf member CUSTA" from the SVI and test with global routing table.

HTH

[ldesmasures]

Hi,

I think you encounter a well known problem : On Nexus family, when activating ip dhcp relay feature, dhcp broadcast are no more forwarded to the local broadcast domain (vlan) due to an internal access-list that redirects packets to CPU :

https://supportforums.cisco.com/document/56651/differences-between-dhcp-relay-nexus7000nxos-and-ip-helper-6500ios

As a workaround, you have to add a relay address to you local DHCP servers...