topic Why ASA 5520 has subinterfaces in Network Security

Why ASA 5520 has subinterfaces

mahesh18 — Mon, 11 Mar 2019 23:06:49 GMT

Hi all,

I am new to ASA cisco 5520 firewall.

I checked config of ASA 5520 it has subinterfaces on gigabit.

Need to know why we create subinterfaces when it has already 4 lan interfaces?

Thanks

MAhesh

Why ASA 5520 has subinterfaces

Kevin P Sheahan — Mon, 14 May 2012 21:00:14 GMT

Subintefaces can be created for different VLANs that all come in on one physical port. Like 'Router on a Stick'.

Kind Regards,

Kevin

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Why ASA 5520 has subinterfaces

varrao — Mon, 14 May 2012 21:51:05 GMT

Apart from what Kevin said, they are also created if you need the other physical interfaces for some future purpose as well, or if the no. of interfaces that you need is greater than the no. of physical interfaces you have on the ASA.

Thanks,
Varun Rao
Security Team,
Cisco TAC

Why ASA 5520 has subinterfaces

mahesh18 — Tue, 15 May 2012 00:44:09 GMT

Hi Varun,

Thanks for reply.

so it means that ASA also use same trunking protocol like 802.1q same like routers and switches?

MAhesh

Re: Why ASA 5520 has subinterfaces

Kevin P Sheahan — Tue, 15 May 2012 00:47:14 GMT

Yes the ASA uses 802.1Q.

Sent from Cisco Technical Support iPhone App

Why ASA 5520 has subinterfaces

mahesh18 — Tue, 15 May 2012 00:49:03 GMT

Hi Kevin and Varun,

Many thanks for your replies.

As i am new to ASA and i have to work on it now as my new jon so will ask more questions

Regards

MAhesh