You might need to override the default gateway for a VMkernel adapter to provide a different gateway for services such as vMotion, Fault Tolerance logging, and Virtual SAN.
Each TCP/IP stack on a host can have only one default gateway. This default gateway is part of the routing table and all services that operate on the TCP/IP stack use it.
For example, the VMkernel adapters vmk0 and vmk1 can be configured on a host.
vmk0 is used for management traffic on the 10.162.10.0/24 subnet, with default gateway 10.162.10.1
vmk1 is used for vMotion traffic on the 172.16.1.0/24 subnet
If you set 172.16.1.1 as the default gateway for vmk1, vMotion uses vmk1 as its egress interface with the gateway 172.16.1.1. The 172.16.1.1 gateway is a part of the vmk1 configuration and is not in the routing table. Only the services that specify vmk1 as an egress interface use this gateway. This provides additional Layer 3 connectivity options for services that need multiple gateways.
You can use the vSphere Web Client or an ESXCLI command to configure the default gateway of a VMkernel adapter.
See Create a VMkernel Adapter on a vSphere Standard Switch, Create a VMkernel Adapter on a Host Associated with a vSphere Distributed Switch, and Configure the VMkernel Adapter Gateway by Using ESXCLI.