PIX/ASA - VLANs in transparent mode?

Unanswered Question
Apr 2nd, 2008
User Badges:

Is there any problem putting an ASA/PIX in transparent mode on an 802.11Q trunk link? I have an internet router that will do NAT to three VLANS and I want to send that trunk through a transparent ASA-5510 for inspection and then onto the trunk port on an internal router. Any problems with this scenario? Or will I have to let the ASA do the NAT and operate in routed mode?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4 (1 ratings)
Loading.
vkapoor5 Wed, 04/09/2008 - 05:27
User Badges:
  • Bronze, 100 points or more

The PIX must be configured for 802.1Q encapsulation. In PIX 6.3 a new feature is added, where PIX can create logical interfaces. Each logical interface corresponds to a VLAN in the switch. Refer to Using VLANs with the Firewall for more information.

http://www.cisco.com/en/US/docs/security/pix/pix63/configuration/guide/bafwcfg.html#wp1113411

vitripat Thu, 04/10/2008 - 10:53
User Badges:
  • Gold, 750 points or more

ASA/PIX when in transparent mode works like a bridge. You can use max. 2 interfaces and these two interfaces need to be part of specific VLANs. It looks like you are connecting these inerfaces to trunk ports carrying multiple VLANs, this will not work. I'm not sure whats your network topology, hence cant suggest if routed mode would be a good option for you. Could you please elaborate more on the network design?


Regards,

Vibhor.

Actions

This Discussion