VM fails to communicate to Layer-3 FQDN targets.

Products

• VMware vSphere ESXi

Issue/Introduction

The issue may only be seen after a vMotion.

The VM can reach Layer-2 targets or by IP, but L3/FQDN targets are unreachable.

Other VMs may work normally on the same host, including on the same NIC/subnet/VLAN as the impacted VM. See VMs intermittently lose network connections after vMotion.

Packet captures may show the VM itself is dropping the packets.

• This could be determined by performing a packet capture in the guest OS directly using a tool like Wireshark, or by confirming the incoming packets are seen at the VM's switchport "VnicRx" capture point, but the replies are not seen at the VM's switchport "VnicTx" with the ESXi pktcap-uw utility. See Packet capture on ESXi using the pktcap-uw tool and pktcap-uw Command Syntax for Capturing Packets for more information about this.

Cause

The in-guest DNS configuration is invalid or incorrect.

Resolution

Set the DNS in the VM's network interface to a valid and reachable DNS target.