I am Cisco certified and have worked for an ISP for the last 5 years. I have made the transition to the LAN side as a Network Administrator so I am a novice at certain things. With that being said, below is the configuration on one of my ASA5520s. I have changed addressing for security, but this is how it looks.

interface GigabitEthernet0/0.2
 nameif Inside
 security-level 100
 ip address 10.x.x.x
interface GigabitEthernet0/0.4
 nameif DMZ
 security-level 50
 ip address 10.x.x.x
interface GigabitEthernet0/1
 nameif Outside
 security-level 0
 ip address 159.x.x.x

My question is this: I have four physical ports on the back of my ASA, why don't they show up in the running config ,,,why?

And my second question: is it ok not to have a VLAN associated with my sub-interfaces?

  • 4
    Please add output from "show context", "sh version" and "show mode" Jul 28, 2014 at 20:41
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    Jan 5, 2021 at 1:34

2 Answers 2


In a word: LICENSE

It could be your license only allows 2 physical interfaces. show version will show your licensed features.

  • 1
    The license could affect the vlan limit. However, I am unaware of any base level ASA which has a limit on the physical connections that doesn't match the actual count of physical connections. The ASA5520 should have 4 GE and 1 FE available for use. Sounds like he is in a context. Jul 28, 2014 at 23:56
  • I agree, he's most likely in a context, but physical interfaces is a field in the license data. (if they are allowed to operate at gig is as well)
    – Ricky
    Jul 29, 2014 at 1:20
  • Yes, but all licenses support all the physical ports. None of them actually restrict the physical ports available. For gig vs fast ethernet, only the 5510 has a license for gig (Sec+ license) which enables gig on 2 of the 5 fast ethernet ports. The 5520 and higher has no license restriction for gig. Jul 29, 2014 at 2:18

Log into the admin context to see the number of interfaces, or use Cisco ASDM if you are a novice with the ASA, it will provide you with a good view of the configuration and performance.

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