Thanks.

The server is all patched up and latest SP is on.

this morning it took 10 minutes for the server to croak.

IIS log was full of PROPFIND requests. They were weird too, because they came from the 
server's own IP address, however the logged on user was a user that belongs to a 
customer in Brazil. I was expecting to see the IP address from Brazil.

Here is a [modified] example:

2003-07-02 11:59:37 [my.server.ip.address] [EMAIL PROTECTED] W3SVC1 SHFEX02 
[my.server.ip.address] 80 PROPFIND /public/ - 500 HTTP/1.1 
exchange.hosting.innerhost.com 
Exchange-Server-Frontend-Proxy/6.0+Mozilla/4.0+(compatible;+MSIE+5.5;+Windows+95)


There were A LOT of these in the log. Mixed up with a few records from the "good" 
customer logons.

I ended up configuring the Default Web Site to deny connections from the server's own 
IP address.  Hopefully this will help.








-----Original Message-----
From: Glenn Corbett [mailto:[EMAIL PROTECTED]
Sent: Wednesday, July 02, 2003 2:11 AM
To: Exchange Discussions
Subject: Re: something is killing IIS on one of my front-ends


Does sound like a DOS attack of some sort (had similar problems with some
standard IIS servers).  If the logs arent too revealing, get your comms guys
to enable incoming logging on the firewalls / firewall routers for traffic
destined for your front-end server.  Should be easy for them to do.

As for blocking the traffic they can do that fairly easily as well, provided
its all from the same / similar places (ours was).  The problem with trying
to block it at the front end server is that by then the box has already seen
the traffic and may be too late to stop it.

Also (as always) make sure you are running the correct suite of patches on
your front-end server.

G.

----- Original Message -----
From: "Fyodorov, Andrey" <[EMAIL PROTECTED]>
To: "Exchange Discussions" <[EMAIL PROTECTED]>
Sent: Tuesday, July 01, 2003 11:06 PM
Subject: something is killing IIS on one of my front-ends


Recently, I have had problems with one of my front-end Exchange 2000
servers. It looks like IIS gets bogged down with something. Eventually IIS
stops responding and resets itself.

Earlier this morning, I was just looking at a few things and noticed that
all of a sudden IIS got 17,000+ connections at a rate of ~50 per second.

I am going to check the logs and try to find out where these connections
came from. Hopefully they are all from one place so that I could block that
source IP address.

And I am fishing for suggestions as to what else I could do to track this
down.

Thanks


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