Problem with "alias" after migrating config from PIX 6.3 to FWSM 3.1

Unanswered Question
Oct 5th, 2007
User Badges:


I've been running two firewalls for some time now, one Pix serving our web applications and one FWSM serving both users and some web application servers.

After the migration the FWSM is set up like this




FWSM----ApplicationNet----PIX(VPN only)




During the migration I pretty much copied all the statics, access-lists and alias entires and adapted them for the FWSM interface names before applying them. No errors there.

Now the old alias commands from the PIX are causing me alot of headache.

The commands I copied lookes something like alias(applicationNetInterface) insideIP OutsideIP. alias(ClientNetInterface) insideIP OutsideIP. Seems ok to me.

But running these on the FWSM causes problems for my incoming internet visitors. I've set up a testing system using 3G and at some point after doing clear xlate I can no longer access my web from my testing system. Nothing in the logs indicating translation errors.

The show connection does however give me strange input.

My static for the web service is like this: static (SERVER,INTERNET)

But I get connection entries from the outside for both the inside and outside IP

sh conn | include

TCP out in idle 0:00:12

TCP out in

sh conn | include

TCP out in idle 0:00:36

How could this be? On the Pix I used the alias command to allow application servers to resolve the web address to an inside address, something I still need to do, and had no problem with the setup.

FWSM must handle this differently

Any input



  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
tstanik Thu, 10/11/2007 - 13:41
User Badges:
  • Bronze, 100 points or more

The application servers maybe resolving the web addresses using internal DNS cache. Thsi could be the reason you are still able to see the inbound and outbound connections. The FWSM has nothing to do in this case.


This Discussion