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Allow traffic through Cisco Pix based on DNS name

Posted on 2008-09-30
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Last Modified: 2012-08-13
HI There,
I have got a big problem. We have got web server based on windows server on cisco pix 515E. We have got sophos Antivirus installed on the server and they have now outsourced their antivirus update servers to third party in highly unporfessional way where their public IP keeps on changing on daily basis.
We earlier have locked down the outbound traffic using ACL but but it does not work and we are forced to use manual update that is a pain.

can you please help me finding out if there is a way to allow DNS name based traffic i.e. sophos.com from firewall so that I can get rid of my troublesome job.
My PIX 515E firewall version is 7.1(2).
Your help is highly appriciated.
Thankss and regards.
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Question by:Prashant0906
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4 Comments
 
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Expert Comment

by:Pugglewuggle
ID: 22608322
Unfortunately this is not possible. PIX and ASA must have a defined IP address for the device. They CAN query dns names but dns names cannot be part of an ACL.
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by:Prashant0906
ID: 22609145
my one ofthe friends was suggesting by using URL filtering does it sound like a soution and does pix provides this ?
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Pugglewuggle earned 500 total points
ID: 22610337
Yes, PIXes do support URL filtering (USING A THIRD PARTY FILTERING PRODUCT) using deep packet inspection.
There are a few catches though:
a) This only works on packets that are "inspectable". That means SSL packets contents cannot be filtered.
b) Requires third party filtering software
c) Biggest kicker: ONLY works with HTTP, HTTPS, FTP. If the AV update download uses any other protocol then this is not an option.
d) This is usually used for content aka porn and other undesirable content.
THE BOTTOM LINE:
I don't think this would work for what you're trying to use it for.
Here is Cisco's info sheet on the technology.
http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_configuration_example09186a008088517b.shtml
 
I ran into a similar problem with a Ukranian spammer trying to abuse our mail server once - I had to manually change ACLs like 10 times a day for a few days until he got tired of trying.
Cisco really needs to think about adding this in the next version of ASA (probably 9.0) and IOS.
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Author Closing Comment

by:Prashant0906
ID: 31501565
Thanks very much for your help.
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