403 Forbidden - OWA

[nix45]

We have Outlook Web Access (OWA) on our Exchange 2000 server published through our ISA 2000 server. Most of the time, everything works fine, but every once in a while users will receive this...

403 Forbidden - The server denies the specified Uniform Resource Locator (URL). Contact the server administrator. (12202)
Internet Security and Acceleration Server

Does anyone know what would cause this intermittent error?

Thanks,
Chris

 

[Knutern]

URLScan activated?

Cheers
Knutern

 

[nix45]

I never heard of it. Is that an option in ISA Management somewhere?

Thanks,
Chris

 

[nix45]

I just did a search for URLScan and found this utility from M$...

http://www.microsoft.com/windows2000/downloads/recommended/urlscan/default.asp

If this is what your talking about, then no, its not installed.

Chris

 

[nix45]

Anyone have any idea what could be causing these intermittent problems? Should I contact M$?

Chris

 

[Knutern]

URLScan is also part of ISA FeaturePack 1. To check whether this is installed, open ISA Management, Extensions, Web Filters and look for "URLScan Filter".



Cheers
Knutern

 

[nix45]

There is nothing under Web Filters.

Chris

 

[Knutern]

Is it possible to reproduce the behavior, i.e. will it always occur with the same e-mail or is it random?

Cheers
Knutern

 

[nix45]

The entire site is down intermittently. I don't see any patterns in when it goes down. Every once in a while I'll be home and I'll try to connect and will get the Forbidden 403 error for no apparent reason.

Thanks,
Chris

 

[Knutern]

Have you checked the information here

http://support.microsoft.com/?id=327003?

Cheers
Knutern

 

[nix45]

Yes, Directory Browsing was turned on for the Exchange virtual server in ESM.

Thanks,
Chris

 

[Knutern]

And if you do OWA from within your LAN, does this still happen?

Cheers
Knutern

 

[nix45]

No, only through the ISA server. For the most part everything works, but this problem does occur every once in awhile. I have no idea what could cause it.

Chris

 

[Knutern]

You don't have the firewall client installed on your Exchange Frontend/Backend servers, i.e. Exchange Servers are configured as a so called SecureNAT client, right?

Cheers
Knutern

 

[nix45]

Yes, SecureNAT, no Firewall Client installed on any servers.

Thanks,
Chris

 

[Knutern]

And any antivirus programs are not allowed to Scan Exchange folders and M:?

Cheers
Knutern

 

[nix45]

We don't have any AV installed on the Exchange server, we do our AV scanning at our mail gateway on another server. The only thing installed on our Exchange server is Exchange.

Thanks,
Chris

 

[Knutern]

The only thing that would help you move on a litte bit would be to use the NETMON on ISA server to monitor what happens. Unless you are using HTTPS, which then would not let you troubleshoot a bit....

I have had numerous problems with our OWA but nothing like this one.

You've googled around for OWA and 403 too?

Cheers
Knutern

 

[nix45]

Yes, of course I've googled. The problem is very intermittent and hard to troubleshoot. I haven't seen the error in about 10 days or so.

Chris

 

[nix45]

fyi, it happened again last night but eventually just started working again (typical piece of M$ software). There was nothing in the logs on the ISA server or the Exchange server and there weren't any network problems that I could find.

Chris