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Sudden Internet loss - 4.Feb.2004 5:39:00 PM

randy_ray

Posts: 59
Joined: 7.Sep.2002
From: Houston, TX
Status: offline

Using ISA in integrated w/ securenat clients I'm experiencing a random but sudden problem of the Internet being inaccessible. If I manually insert a proxy setting in the browser I can reach the Internet w/ no problem. As soon as I remove the proxy setting there is no Internet. There are no event errors and restarting the services does nothing. Eventually Internet access returns without using a proxy setting. Are there any known hacks or attacks that kill Internet access. I did notice a long list of port scans from a single IP just before Internet stopped. Oh, and there was one concerning the cache, event 14197.

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RE: Sudden Internet loss - 4.Feb.2004 5:49:00 PM

ppeetoom

Posts: 262
Joined: 22.Dec.2003
From: The Netherlands
Status: offline

Take a look at your listener(s). Make sure they are only listening on your internal NIC. And secondly, take a look at your HTTP Redirector (appl. filter). Make sure you don't use the combination of routing all requests through your Web Proxy AND using authentication on the Web Proxy.

Let us know the results........

(in reply to randy_ray)

Post #: 2

RE: Sudden Internet loss - 4.Feb.2004 6:30:00 PM

randy_ray

Posts: 59
Joined: 7.Sep.2002
From: Houston, TX
Status: offline

I have listening on the Internal and "use the same configuration" selected for the external. There is not authentication set and all clients go through the one ISA server for Internet access and content filtering.

(in reply to randy_ray)

Post #: 3

RE: Sudden Internet loss - 4.Feb.2004 7:45:00 PM

ppeetoom

Posts: 262
Joined: 22.Dec.2003
From: The Netherlands
Status: offline

That means that you are hosting a http proxy for the world wide web. Set the listener to only listen on your internal NIC. It might help you solve the problem.

Let us know and good luck.........

(in reply to randy_ray)

Post #: 4

RE: Sudden Internet loss - 4.Feb.2004 8:23:00 PM

randy_ray

Posts: 59
Joined: 7.Sep.2002
From: Houston, TX
Status: offline

Hmmm... I think we may be off on something. There's no way to turn off the listener on either outbound or inbound. Doesn't ISA need to "listen" for inbound?

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Post #: 5

RE: Sudden Internet loss - 4.Feb.2004 8:36:00 PM

ppeetoom

Posts: 262
Joined: 22.Dec.2003
From: The Netherlands
Status: offline

Read the following article. It will give you a good idea what to do:

http://www.isaserver.org/tutorials/Configuring_ISA_outbound_web_listener.html

Furthermore, select "Configure listeners individually per IP adress" on the inbound web listener and leave the listbox empty. This will disable the Web Proxy for the www.

Good luck..........

[ February 04, 2004, 09:18 PM: Message edited by: Groofster ]

(in reply to randy_ray)

Post #: 6

RE: Sudden Internet loss - 4.Feb.2004 9:53:00 PM

randy_ray

Posts: 59
Joined: 7.Sep.2002
From: Houston, TX
Status: offline

If I disable the inbound listener won't that affect web publishing since ISA can't listen for requests?

In regards to my original problem, suddenly I have Ineternet access without a manual proxy setting. I ended up rebooting the server one more time. So the cause of the problem is still uknown, without changing listeners.

Thanks for the advice and I'll check out the link.

(in reply to randy_ray)

Post #: 7