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Internet Explorer - ASA 5520

Arild Amundsen
Level 1
Level 1

Hi,

I have a trick case with a ASA 5520 and a intranet in Internet Explorer. There is a picture, flash and document manager and the trafic get blocked when using IE, but not in Firefox. The intranet is using port 80. Anyone else seen something like this?

31 Replies 31

Farrukh Haroon
VIP Alumni
VIP Alumni

Most probably the issue is not with the firewall (ASA) and the real issue lies in the browser settings.

Regards

Farrukh

Hi,

Thanks for your quick replay.

I tought so to but the intranet is funktion quite well outside the network ex. from my home net. And i get an Access Denied in the ASA logg on traffic to the intranet when i use IE inside my net, but strangely not in Firefox.

Please give more details about the topology, configuration/inspections enabled on the ASA.

Regards

Farrukh

Http inspection has default settings.

Her are the message i get in tha ASA logg when using IE.

Deny TCP (no connection) from x.x.x.x/2997 to x.x.x.x/80 flags ACK on interface Innside

Deny TCP (no connection) from x.x.x.x/2997 to x.x.x.x/80 flags FIN ACK on interface Innside

Teardown TCP connection 197682186 for Internett:x.x.x.x/80 to Innside:x.x.x.x/2997 duration 0:00:28 bytes 304213 Flow closed by inspection

Access denied URL SRC x.x.x.x DEST x.x.x.x on interface Innside

This is regular http traffic and it is working in Firefox from the same pc and settings.

The logs seem to come from the Internet and not the Intranet?

Regards

Farrukh

This message comes from the webserver hosting the intranet.

Teardown TCP connection 197682186 for Internett:x.x.x.x/80 to Innside:x.x.x.x/2997 duration 0:00:28 bytes 304213 Flow closed by inspection

I can't understand why inspection is closing the connection when IE is used, but works in FF. Maybe it is something in the way browser handlling the site and is there anything we can set in ASA to prevent/allow this?

I'm still not clear with your topology.

On which zone is your web server? "Internett" zone? From where are you testing ? LAN = "Innside"?

Which version of ASA are you running?

What do you have under IE:

IE >> Tools >> Advanced >> HTTP 1.1 Settings

Regards

farrukh

The webserver are not in "my net". We are delivering applications via Citrix to our users. I am testing this from my inside, with the same setting the users have.

So the traffic are like this:

Terminal Server -> ASA -> Internet -> Webserver

ASA version: ASA 5520 with image asa721-k8

And we are using http 1.1 settings

Can you try permitting this 'return' traffic or disabling the HTTP inspection to test this out?

Hi again,

I am not very experienced with ASA, so how would turning of http inspection affect the rest of the traffic?

Disabling should not affect other traffic, but just to be on the safe side you can just disable it for your specific server, please have a look at:

http://www.cisco.com/en/US/products/hw/vpndevc/ps2030/products_tech_note09186a008085283d.shtml

Regards

Farrukh

Hi,

Have tried the suggested solutions, but still same errors in the asa log. I have tried with a new asa 5505 with default settings and there it is working, the only differens is that it is a newer image on the 5505 (7.2(2))

Best Regards

Can you post the output of the following command from both boxes:

show run all policy-map

show run service-policy

Then on the troublesome box,

clear asp drop

immediately test the problematic server connection via IE, then paste output of

show asp drop

Regards

Farrukh

Hi, Farrukh,

Will do that tomorrow, thanks for your replay.

Regards

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