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Mac address for gateway interface on layer switches

suthomas1
Level 6
Level 6

Hello All,

We have  a network of layer 2 switches which link upto firewalls(holds layer3 gateway interface for subnets).

About 04 new vlans were added to layer 2 switches, corresponding layer3 created on firewalls & trunks enabled for these links.

Now, none of these new vlans are actually being assigned to any individual ports as "access vlans". However, these are available across many

trunk ports ( which link to servers that use trunk interfaces to get required vlans into them ).

In such a case, will the layer 2 address of the gateway interface(of firewall) will be visible on the layer 2 switches using sh mac-address table?

The gateway can be pinged from layer2 switches , however i can't see the mac of the gateway on these switches. Is it normal or because of no access ports being assigned towards these vlans?

Appreciate all inputs.Thanks in advance.

1 Accepted Solution

Accepted Solutions

Do you have VTP pruning enabled?  If so, the access layer switch trunk links will have VLANs pruned off the trunk links if there are no access ports assigned to those VLANs.  

As soon as there are any broadcast or unicast frames on the new VLANs, the switches should learn of the gateway MAC addresses.

View solution in original post

2 Replies 2

Midhun Jackson
Level 1
Level 1

You should see the MAC address listed against the trunk port. Have you checked the mac-table after pinging the gateway?

Do you have VTP pruning enabled?  If so, the access layer switch trunk links will have VLANs pruned off the trunk links if there are no access ports assigned to those VLANs.  

As soon as there are any broadcast or unicast frames on the new VLANs, the switches should learn of the gateway MAC addresses.

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