Pings are not passing over GRE tunnel

Products

• VMware NSX

Issue/Introduction

• ICMP ping from a VM on an overlay segment through a T0 GRE tunnel is failing.
• Other traffic such as SSH works without issue.
• The T0 is in active-standby .
• Packet capture on the ESX host where the active T0 edge is running shows ICMP requests, but no response.
  
  pktcap-uw --uplink vmnic[X] --capture UplinkSndKernel,UplinkRcvKernel -o - | tcpdump-uw -enr - | grep "[source-ip]"
[Timestamp] [src-mac] > [dst-mac], ethertype IPv4 (0x0800), length 122: [gre-src-ip] > [gre-dst-ip]: GREv0, proto IPv4 (0x0800), length 88: [vm-src-ip] > [vm-dst-ip]: ICMP echo request, id [ID], seq 1, length 64
[Timestamp] [src-mac] > [dst-mac], ethertype IPv4 (0x0800), length 122: [gre-src-ip] > [gre-dst-ip]: GREv0, proto IPv4 (0x0800), length 88: [vm-src-ip] > [vm-dst-ip]: ICMP echo request, id [ID], seq 2, length 64
  
  
• ESX host has NIC Intel(R) Ethernet Controller E810-C for SFP with driver ICEN 2.2.2.0 and firmware 4.70.

Environment

VMware NSX

Resolution

Downgrade ICEN driver to 2.1.1.0