L2 trunks between 3 Cisco switches

tshooter — Wed, 28 Feb 2024 00:56:24 GMT

THis was working in vwire just fine with two vwires.
1/1 to 1/3 vwire 1
1/5 to 1/6 vwire 2

Now we want to go to Layer 2, here is the configuration. I am only adding L2 sub interfaces to the firewall.
1st trunk:
--CISCO SW1 TRUNKED INTERFACE ALLOWING ONLY VLAN 9 >> FW >> SW3 CISCO TRUNKED INTERFACE ALLOWING ONLY VLAN 9.
--FW VLAN 9 tagged on L2 eth1/1.9(trust) going to L2 eth1/3.9(untrust) , both interfaces in a VLAN.

2nd trunk SW2 to SW3

CISCO SW2 TRUNK INTERFACE ALLOWING ONLY VLAN 6,42,52 >> FW >> SW3 CISCO TRUNKED INTERFACE ALLOWING ONLY VLAN 6,42,52.

FW VLAN 6 tagged on L2 eth1/5.6(trust zone) going to L2 eth1/6.6(untrust zone) , both interfaces in a VLAN.
FW VLAN 42 tagged on L2 eth1/5.42(trust zone) going to L2 eth1/6.6(untrust zone) , both interfaces in a VLAN.

FW VLAN 52 tagged on L2 eth1/5.52(trust zone) going to L2 eth1/6.52(untrust zone) , both interfaces in a VLAN.

What am I missing here? Any config examples with trunking vlans across the palo? two trunks across in this case.

TRUNK 1 = SW1 <> FW <> SW3 vlan 8
TRUNK 2 = SW2 <> FW <> SW3 vlan 6,42,52

Trying to do this without L3 subinterfaces.. L2 should work between two trunks that were working with vwire..

Re: L2 trunks between 3 Cisco switches

reaper — Fri, 01 Mar 2024 11:59:46 GMT

This should work, but did you set all the zones identical? (all 'trust' and 'untrust') I'd recommend using unique sets (trust6, untrust6, trust 42, untrust42) for each vlan, else you could allow vlan hopping

for VLAN 42 you have the second interface set as 1/6.6, is that a typo?

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L2 trunks between 3 Cisco switches

Re: L2 trunks between 3 Cisco switches