topic Re: Same Vlan on Multiple Subinterfaces Cisco ASA 5506-x in Network Security

Same Vlan on Multiple Subinterfaces Cisco ASA 5506-x

thom784e — Wed, 27 Sep 2023 12:22:50 GMT

Hello.

i'm trying to setup some subinterfaces the following way

Interface GigabitEthernet1/7.2
Vlan 2
192.168.2.1
Interface GigabitEthernet 1/8.2
Vlan 2
192.168.2.1

how ever it doesn't allow me to put vlan 2 on the 1/8.2 subinterface
"ERROR: Vlan 2 exists in the global vlans table"

I am trying to setup the sub interfaces as gateways for the users/machines on each vlan.

Port 1/7 is linked to switch-01 and port 1/8 is linked to switch-02

now i do realize that i probably cannot have 192.168.2.1 as the IP on 2 subinterfaces either, but i am not sure how to properly do the setup otherwise so i will figure that issue out at a later point

i also plan on doing a HA (active/standby) with FW01 as master to help with redundancy.
if anything else appears odd and you have feedback i highly appriciate it 🙂

Re: Same Vlan on Multiple Subinterfaces Cisco ASA 5506-x

balaji.bandi — Wed, 27 Sep 2023 12:58:44 GMT

You need to run HSRP depends on the requirement if this configuration you apply in the switch ?

Also i expecte ASA FW Active /Standby config - please confirm ?

Re: Same Vlan on Multiple Subinterfaces Cisco ASA 5506-x

thom784e — Thu, 28 Sep 2023 06:33:58 GMT

yes, it will be an active/standby config.

the switches are L2 and will not have a lot configured on them.

Re: Same Vlan on Multiple Subinterfaces Cisco ASA 5506-x

thom784e — Thu, 28 Sep 2023 06:46:25 GMT

we have since then found out that it is not possible to do HSRP on cisco asa 5506-x and we have decided to place 2 routers between the L2 switches and the firewalls