6.5.1

Table Of Contents
Solution
Check which switch has lost uplink redundancy on the host. Connect at least one more physical NIC on
the host to this switch and reset the alarm to green. You can use the vSphere Web Client or the
ESXi Shell.
If a physical NIC is down, try to bring it back up by using the ESXi Shell on the host.
For information about using the networking commands in the ESXi Shell, see vSphere Command-Line
Interface Reference. For information about configuring networking on a host in the vSphere Web Client,
see vSphere Networking.
Virtual Machines Lose Connectivity After Changing the
Uplink Failover Order of a Distributed Port Group
Changes in the failover NIC order on a distributed port group cause the virtual machines associated with
the group to disconnect from the external network.
Problem
After you rearrange the uplinks in the failover groups for a distributed port group in vCenter Server, for
example, by using the vSphere Web Client, some virtual machines in the port group can no longer access
the external network.
Cause
After changing the failover order, many reasons might cause virtual machines to lose connectivity to the
external network.
n
The host that runs the virtual machines does not have physical NICs associated with the uplinks that
are set to active or standby. All uplinks that are associated with physical NICs from the host for the
port group are moved to unused.
n
A Link Aggregation Group (LAG) that has no physical NICs from the host is set as the only active
uplink according to the requirements for using LACP in vSphere.
n
If the virtual machine traffic is separated in VLANs, the host physical adapters for the active uplinks
might be connected to trunk ports on the physical switch that do not handle traffic from these VLANs.
n
If the port group is configured with IP hash load balancing policy, an active uplink adapter is
connected to a physical switch port that might not be in an EtherChannel.
You can examine the connectivity of the virtual machines in the port group to associated host uplinks and
uplink adapters from the central topology diagram of the distributed switch or from the proxy switch
diagram for the host.
Solution
n
Restore the failover order with the uplink that is associated with a single physical NIC on the host
back to active.
vSphere Troubleshooting
VMware, Inc. 92