VMware vSphere ESXi Host Fails to Ping Local Gateway and Does Not Learn ARP Entry

Products

• VMware vSphere ESXi

Issue/Introduction

• A newly installed VMware vSphere ESXi host cannot ping the local gateway and does not learn an ARP entry.
• When testing an ESXi host management network configuration via the Direct Console User Interface (DCUI), the host is unable to ping the default gateway or DNS servers.
• If the host is not new and was already working previously, then it would show as "Not Responding" in vCenter Server.
• Packet captures may show outbound ARP requests leaving the host but no corresponding ARP replies returning from the upstream physical network:
  

 

Environment

VMware ESXi 7.x
VMware ESXi 8.x

Cause

The network configuration is inconsistent with the physical switch port configuration, or the physical NICs are not in a connected status. This can be caused by:

• VLAN tag mismatches.
• Physical port failures or upstream switch issue.
• Inconsistent LACP/LAG configurations.

Resolution

1. Verify Physical Connectivity: Ensure cables are seated and optics are approved. Run the following command to verify status: following Confirm both Admin and Link status are "Up."

   esxcli network nic list

2. Validate Layer 2 Configuration: Ensure the physical switch port configuration matches the ESXi host (VLAN ID, MTU, etc.).
   • Perform a vmkping to another host on the same subnet to isolate the gateway: 

     vmkping -I vmk0 [target_IP]

   • If no ARP replies are received, verify the VLAN ID and subnet mask for vmk0.
     
     
   • Perform packet capture on the uplinks to see if traffic can be seen on the VLAN. 

     pktcap-uw -- uplink vmnic# -- vlan <VLAN ID> -- dir 1 -c 2

   • Identify which VLANs are visible for each uplink.  

     esxcli network nic vlan stats set -n vmnic# -e true
     esxcli network nic vlan stats get -n vmnic#

     Note: Disable VLAN stats after troubleshooting

     esxcli network nic vlan stats set -n vmnic# -e false

   • Confirm if LACP is in use, as it is only supported on vSphere Distributed Switches (vDS), not Standard Switches.
     
     
3. Bypass Isolated Paths: If an upstream block is suspected, try provisioning alternative adapters (e.g., vmnic0 or vmnic2) and moving the management traffic to a different validated VLAN.
4. Validate NIC Driver/Firmware compatibility: Ensure the installed NIC driver and firmware match the latest approved versions listed on the Hardware Compatibility List (HCL). See Download Broadcom products and software for steps to download.
5. Engage Hardware Vendor: Engage the respective hardware vendor for further investigation if the NIC is verified as faulty.

Additional Information

Testing VMkernel network connectivity with the vmkping command