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Connection Issues

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Connection Issues - 15.Dec.2009 1:35:31 AM   
LoganYoung

 

Posts: 3
Joined: 15.Dec.2009
From: South Africa
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Just to be clear from the start, I'm a complete novice with regard to server environments and network infrastructure...

At work, every computer on the network connects to the box that's running the domain controller and DSN. This box connects via network to the box where ISA Server is running (which is connected directly to the phone line for our internet connection).

Each client computer funs a little application called Firewall Client with which we connect to the ISA Server in order to get internet access.
Since Friday, there's been something really wierd going on with the internet connection and I strongly suspect that there might be something in ISA Server that's causing the problem.
It seems every 2 hours, almost all the computers that are running Firewall Client lose the internet connection and Firewall Client reports "ISA Server <server name> is inaccessible".

I say almost all the computers on the network because the only ones that don't seem affected are the pc's beloning to the MD, the MD's PA, the HR Manager and the CIO.
Everyone else (IT, call centre, admin, and quality control) - we all lose our connection and as a result, can't send and receive mail, browse online, etc.

The reason I suspect the box running ISA Server is because 9 times out of 10, restarting that box solves the problem. Meanwhile, there is no dramatic increase or decrease in proxy or firewall traffic and we've set up the firewall to accept unlimited connections.

Any help to pinpoint possible causes of this problem will be greatly appreciated.
Thank you for your time.

_____________________________

Regards,
Logan

If you can think of a problem, there's a solution waiting to be found - Me
Post #: 1
RE: Connection Issues - 15.Dec.2009 9:31:16 AM   
Rotorblade

 

Posts: 1348
Joined: 27.Feb.2007
Status: offline
Logan,

Well, sounds like you definitely have a problem some where. To help you and to narrow it down a bit; take a look at the ISA serverís event logs for any anomalies that might be associated to your issue. ISA monitoring is also a good source to look for issues. It sounds like the Firewall service is shutting down on you but without some solid troubleshooting detail it will be like trying to find a needle in a haystack!

RB   



_____________________________

David Melvin
Ohio
MCSE: Security 2003, MCSA:Security 2003

(in reply to LoganYoung)
Post #: 2
RE: Connection Issues - 15.Dec.2009 9:36:04 AM   
Rotorblade

 

Posts: 1348
Joined: 27.Feb.2007
Status: offline
I probably should also ask the # 1 support question; what has been changed since Friday to possibly cause an issue? Software, Service Packs or updates applied? What ISA version are you running?

RB

_____________________________

David Melvin
Ohio
MCSE: Security 2003, MCSA:Security 2003

(in reply to Rotorblade)
Post #: 3
RE: Connection Issues - 17.Dec.2009 2:18:56 AM   
LoganYoung

 

Posts: 3
Joined: 15.Dec.2009
From: South Africa
Status: offline
I think it's necessary at this point that I make it clear that I'm not looking after the ISA server, my boss is. I know he's been playing around with settings this week, but I don't know what he's changed.

If the problem is that the firewall is dropping, I don't see how that could affect web traffic as the only thing that goes through the firewall is email. Granted, when the problem does occur, mail goes down too, but the firewall on ISA shouldn't affect the proxy should it?

As it turns out, I have gone through the event log and I didn't find anything suspicious other than issues with the DHCP being unable to assign IP addresses here and there and there was something abou t the DNS, but I think we got that one sorted out.

_____________________________

Regards,
Logan

If you can think of a problem, there's a solution waiting to be found - Me

(in reply to LoganYoung)
Post #: 4
RE: Connection Issues - 17.Dec.2009 4:03:20 AM   
LoganYoung

 

Posts: 3
Joined: 15.Dec.2009
From: South Africa
Status: offline
My Firewall Client just reported a few minutes ago that "ISA Server Maudot2 is inaccessible".
Immediately I VNC'd onto the server and checked the event log. Under the Application log, I found the following event:
Event Type:	Error
Event Source:	Microsoft Web Proxy
Event Category:	None
Event ID:	14197
Date:		12/17/2009
Time:		10:38:58 AM
User:		N/A
Computer:	MAUDOT2
Description:
ISA Server failed to write content to cache file. The error code in the Data area of the event properties indicates the cause of the failure. 
Data:
0000: 05 40 00 80               .@.?    


As server's and proxies aren't my are of expertise, I've got no idea if this is related to the problems, but I'm hoping you can tell me what it means.

On a side note, it sort of makes sense to me that this is what's causing the problem based on what my boss told me this morning: that email goes through the firewall, and web requests go through the proxy. It doesn't make sense though that the mails would also go down when this happens.

_____________________________

Regards,
Logan

If you can think of a problem, there's a solution waiting to be found - Me

(in reply to LoganYoung)
Post #: 5
RE: Connection Issues - 18.Dec.2009 9:44:03 AM   
Rotorblade

 

Posts: 1348
Joined: 27.Feb.2007
Status: offline
quote:


Granted, when the problem does occur, mail goes down too, but the firewall on ISA shouldn't affect the proxy should it?


Sure it would.

Based on what you have shared; I would be looking at the hardware. Sounds like you have a disk I/O problem. Is the ISA cache on a separate disk array/volume? The cache could be corrupted? After running some disk diagnostics; clear the ISA cache by deleting it then redefine a new cache.


HTH

RB

_____________________________

David Melvin
Ohio
MCSE: Security 2003, MCSA:Security 2003

(in reply to LoganYoung)
Post #: 6
RE: Connection Issues - 18.Dec.2009 9:48:39 AM   
Rotorblade

 

Posts: 1348
Joined: 27.Feb.2007
Status: offline
quote:


clear the ISA cache by deleting it then redefine a new cache.


Using the ISA MMC, Configuration, Cache, Tasks, Define Cache Drives.

_____________________________

David Melvin
Ohio
MCSE: Security 2003, MCSA:Security 2003

(in reply to Rotorblade)
Post #: 7

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