topic You can use any interface for in Network Security

ASA Outside Interface and Static/Identity NAT

johnlloyd_13 — Tue, 12 Mar 2019 08:35:34 GMT

hi all,

sorry i feel like a noob again. it's been a while since i designed/configured from scratch.

a client wants to use an 'outside' interface on an ASA5516-X other than g0/0. is it possible to use g0/1 or other ports as outside interface?

i remember configuring another outside interface other than e0/0 on a 5505 and i think it didn't work.

also is below identity NAT possible?

object network NETWORK-1

subnet 192.168.100.0 255.255.255.0

nat (inside,outside) static NETWORK-1

You can use any interface for

Karsten Iwen — Sun, 27 Nov 2016 10:10:43 GMT

You can use any interface for any "role" in the network. The ASA doesn't care which interface in inside, outside and so on. Also the names are not relevant any more. Very long time ago (when we used the PIX) there were some restrictions, but these are not relevant any more. The only restriction is that the management-port can't be used for through-traffic on some of the ASAs.

For your second question: Yes, that can be done. But be careful that you get the right order of operation. For NATs like these, it's likely that you better place them in section one with "manual/twice NAT" instead to place them in section two (auto/object NAT).

hi karsten,

johnlloyd_13 — Sun, 27 Nov 2016 10:36:55 GMT

hi karsten,

thanks! so i reviewed again NAT from this link:

https://supportforums.cisco.com/document/132066/asa-nat-83-nat-operation-and-configuration-format-cli#TWICE-TYPE

so the NAT on my original post would fall under 'section 1' correct?

coz i have several PAT statements after this one. should i put the keyword 'after-auto' on my PAT?

originally i wrote:

object network NETWORK-1

subnet 192.168.100.0 255.255.255.0

nat (inside,outside) static NETWORK-1

object network NETWORK-192.168.180.0-24
description GUEST-WIFI
subnet 192.168.180.0 255.255.255.0
nat (GUEST-WIFI,outside) dynamic interface

should i do below instead?

object network NETWORK-1

subnet 192.168.100.0 255.255.255.0

nat (inside,outside) 1 source static NETWORK-1

object network NETWORK-10.100.180.0-24
description LAN
subnet 10.100.180.0 255.255.255.0
nat (inside,outside) after-auto 1 dynamic interface

object network NETWORK-192.168.180.0-24
description GUEST-WIFI
subnet 192.168.180.0 255.255.255.0
nat (GUEST-WIFI,outside) after-auto 2 dynamic interface