VLAN Bridging - Having Issues After Bridging VLANs Into The Same Subnet

By esupport posted Mar 30, 2020 02:12 PM

  
Q:

Why do I run into problems when I bridge two VLANs into the same subnet/domain?



A:

By default, the VLANs on the switch all share the same MAC address.  This can cause issues when bridging multiple VLANs into the same subnet.  You can manually change the VLAN MAC address using the following command:

vlan <x> ip-recv-mac-address xxxxxx-xxxxxx

 

Solution:  Try changing the MAC address on one or both VLANs to a unique address.

Example:
Port 1 is a member of VLAN 48.
Port 2 is a member of VLAN 49.​
Ports 1 and 2 are bridged together into the same subnet.

Manually change the VLAN MAC address to a unique address:
vlan 48 ip-recv-mac-address 665544-332211
vlan 49 ip-recv-mac-address 665555-444444

This allows both VLANs to carry traffic for the same subnet without having ARP issues.

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