NSX-T T1 dhcp relay is not forwarding DHCPNAK packets to the client.

Products

• VMware NSX

Issue/Introduction

Symptoms:
T1 doesn't forward that DHCPNAK packet to the client, so the client keeps on generating DHCP requests trying to get the old IP and after some time it times out

Environment

VMware NSX-T

Cause

When DHCP relay on DR relay the DHCPNAK message, the yiddr field would be zero since it is NAK message which means it does not allocate IP to client. The dhcp relay use the 0.0.0.0 as destination IP for the forwarding reply packet to client. This cause it is route by DR default route.

Resolution

This known issue is fixed in NSX-T 3.1.3 and NSX-T 3.0.3.2