RE: OT: Tool to identify Evaluate DNS clients?

  • From: "Thomas W Shinder" <tshinder@xxxxxxxxxxx>
  • To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
  • Date: Wed, 18 Aug 2004 06:22:41 -0500

Hi William,

Again, if you run NetMon for three seconds and look at the decodes, you
should be able to figure it out. You'll see a lot of SMTP traffic and
DNS traffic that doesn't look quite right. 

Putting together those findings with SMTP server logs, DNS server logs,
the ISA firewall logs, will help solve this problem. You can use a tool
like Packetyzer to make things a bit easier.

HTH,

Tom
www.isaserver.org/shinder
Get the book!
Tom and Deb Shinder's Configuring ISA Server 2004
http://tinyurl.com/3xqb7
MVP -- ISA Firewalls



-----Original Message-----
From: William Robertson [mailto:robertson.william@xxxxxxxxxxxxxx] 
Sent: Wednesday, August 18, 2004 12:47 AM
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: OT: Tool to identify Evaluate DNS clients?


http://www.ISAserver.org

Thanks Tom, unfortunately I don't have Exchange, I've only got a Linux
SendMail server - with very limited options regarding the control of
mail
etc.

You got a good point though - I do believe the problem is a symptom of
bogus
addresses being queried against my DNS server and then just causing an
inherent DoS. The problem is trying to find the culprit that is causing
this
problem... I'll try again and look into the Packet Sniff's, was just
hoping
that someone out there may have heard of some reporting utility that
could
assist with aggregating the DNS logs or something.

Anyway, thanks again,
Cheers
William R.

-----Original Message-----
From: Thomas W Shinder [mailto:tshinder@xxxxxxxxxxx] 
Sent: 17 August 2004 04:36 PM
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: OT: Tool to identify Evaluate DNS clients?

http://www.ISAserver.org

Hi William,

Could be something that I saw not too long ago on my own corpnet. Is
your Exchange Server getting flooded with bogus destination e-mail
addresses? The NDR and notification messages might be trying to resolve
bogus domain names. Turn off NDR and notification messages and it will
stop. Check your queues and badmail folders to confirm.

HTH,

Tom
www.isaserver.org/shinder
Get the book!
Tom and Deb Shinder's Configuring ISA Server 2004
http://tinyurl.com/3xqb7
MVP -- ISA Firewalls



-----Original Message-----
From: William Robertson [mailto:robertson.william@xxxxxxxxxxxxxx] 
Sent: Tuesday, August 17, 2004 8:36 AM
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: OT: Tool to identify Evaluate DNS clients?


http://www.ISAserver.org

Hmmm, tried to avoid saying that... what I am seeing is that my internet
link is saturated with outbound DNS requests. In my Firewall Logs I can
only
see my 2 DNS servers as doing the requests for outbound DNS queries,
which
is the way it is meant to be...

But what I am presuming is that some client workstation is
generating/causing a helluva lot of DNS requests, either via directly
contacting my DNS Server, or by requesting Port 80 traffic which will
then
route via my Firewall to my DNS Server, and then back through my
firewall.

So I was hoping to tackle the easier scenario first, and hoping to
generate
some sort of realtime/historical report which will show me the "Top
Requesters" for DNS resolution against my DNS Servers...

Is there something like this?

-----Original Message-----
From: Thomas W Shinder [mailto:tshinder@xxxxxxxxxxx] 
Sent: 17 August 2004 03:24 PM
To: [ISAserver.org Discussion List]
Subject: [isalist] RE: OT: Tool to identify Evaluate DNS clients?

http://www.ISAserver.org

Hi William,

Are you saying that the ISA firewall is generating a lot of DNS traffic?

Thanks!

Tom
www.isaserver.org/shinder
Get the book!
Tom and Deb Shinder's Configuring ISA Server 2004
http://tinyurl.com/3xqb7
MVP -- ISA Firewalls



-----Original Message-----
From: William Robertson [mailto:robertson.william@xxxxxxxxxxxxxx] 
Sent: Tuesday, August 17, 2004 6:11 AM
To: [ISAserver.org Discussion List]
Subject: [isalist] OT: Tool to identify Evaluate DNS clients?


http://www.ISAserver.org

Hi there

I seem to be experiencing an extreme amount of outbound DNS requests via
my
FIREWALL to my local DNS Servers. I am quite confident that this traffic
is
not legitimate and is most likely the source of an *evil* application ;)

Does anyone know if it is at all possible to "query" a Win2K DNS Server
to
see which clients are in fact making the DNS requests? I.e. I want to be
able to see which PC is at the top of the list with regards the number
of
queries, or at least see which "dodgy" domain names are being requested
from
which PC's...

Any ideas?
Thanks
William R.

---------------------------------------------------------------------
Everything in this e-mail and attachments relating to the official 
business of Columbus Stainless is proprietary to the company. It is 
confidential, legally privileged and protected by law. Columbus 
Stainless does not own and endorse any other content. Views and 
opinions are those of the sender unless clearly stated as being that 
of Columbus Stainless. The person addressed in the e-mail is the sole 
authorised recipient.  Please notify the sender immediately if it has 
unintentionally reached you and do not read, disclose or use the 
content in any way. Whilst all reasonable steps are taken to ensure 
the accuracy and integrity of information and data transmitted 
electronically and to preserve the confidentiality thereof, no 
liability or responsibility whatsoever is accepted if information or 
data is,for whatever reason, corrupted or does not reach its intended
destination.
---------------------------------------------------------------------

------------------------------------------------------
List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist
ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp
ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ
------------------------------------------------------
Other Internet Software Marketing Sites:
World of Windows Networking: http://www.windowsnetworking.com
Leading Network Software Directory: http://www.serverfiles.com
No.1 Exchange Server Resource Site: http://www.msexchange.org
Windows Security Resource Site: http://www.windowsecurity.com/
Network Security Library: http://www.secinf.net/
Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com
------------------------------------------------------
You are currently subscribed to this ISAserver.org Discussion List as:
tshinder@xxxxxxxxxxxxxxxxxx
To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=isalist
Report abuse to listadmin@xxxxxxxxxxxxx

------------------------------------------------------
List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist
ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp
ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ
------------------------------------------------------
Other Internet Software Marketing Sites:
World of Windows Networking: http://www.windowsnetworking.com
Leading Network Software Directory: http://www.serverfiles.com
No.1 Exchange Server Resource Site: http://www.msexchange.org
Windows Security Resource Site: http://www.windowsecurity.com/
Network Security Library: http://www.secinf.net/
Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com
------------------------------------------------------
You are currently subscribed to this ISAserver.org Discussion List as:
robertson.william@xxxxxxxxxxxxxx
To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=isalist
Report abuse to listadmin@xxxxxxxxxxxxx

---------------------------------------------------------------------
Everything in this e-mail and attachments relating to the official 
business of Columbus Stainless is proprietary to the company. It is 
confidential, legally privileged and protected by law. Columbus 
Stainless does not own and endorse any other content. Views and 
opinions are those of the sender unless clearly stated as being that 
of Columbus Stainless. The person addressed in the e-mail is the sole 
authorised recipient.  Please notify the sender immediately if it has 
unintentionally reached you and do not read, disclose or use the 
content in any way. Whilst all reasonable steps are taken to ensure 
the accuracy and integrity of information and data transmitted 
electronically and to preserve the confidentiality thereof, no 
liability or responsibility whatsoever is accepted if information or 
data is,for whatever reason, corrupted or does not reach its intended
destination.
---------------------------------------------------------------------

------------------------------------------------------
List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist
ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp
ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ
------------------------------------------------------
Other Internet Software Marketing Sites:
World of Windows Networking: http://www.windowsnetworking.com
Leading Network Software Directory: http://www.serverfiles.com
No.1 Exchange Server Resource Site: http://www.msexchange.org
Windows Security Resource Site: http://www.windowsecurity.com/
Network Security Library: http://www.secinf.net/
Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com
------------------------------------------------------
You are currently subscribed to this ISAserver.org Discussion List as:
tshinder@xxxxxxxxxxxxxxxxxx
To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=isalist
Report abuse to listadmin@xxxxxxxxxxxxx

------------------------------------------------------
List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist
ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp
ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ
------------------------------------------------------
Other Internet Software Marketing Sites:
World of Windows Networking: http://www.windowsnetworking.com
Leading Network Software Directory: http://www.serverfiles.com
No.1 Exchange Server Resource Site: http://www.msexchange.org
Windows Security Resource Site: http://www.windowsecurity.com/
Network Security Library: http://www.secinf.net/
Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com
------------------------------------------------------
You are currently subscribed to this ISAserver.org Discussion List as:
robertson.william@xxxxxxxxxxxxxx
To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=isalist
Report abuse to listadmin@xxxxxxxxxxxxx

---------------------------------------------------------------------
Everything in this e-mail and attachments relating to the official 
business of Columbus Stainless is proprietary to the company. It is 
confidential, legally privileged and protected by law. Columbus 
Stainless does not own and endorse any other content. Views and 
opinions are those of the sender unless clearly stated as being that 
of Columbus Stainless. The person addressed in the e-mail is the sole 
authorised recipient.  Please notify the sender immediately if it has 
unintentionally reached you and do not read, disclose or use the 
content in any way. Whilst all reasonable steps are taken to ensure 
the accuracy and integrity of information and data transmitted 
electronically and to preserve the confidentiality thereof, no 
liability or responsibility whatsoever is accepted if information or 
data is,for whatever reason, corrupted or does not reach its intended
destination.
---------------------------------------------------------------------

------------------------------------------------------
List Archives: http://www.webelists.com/cgi/lyris.pl?enter=isalist
ISA Server Newsletter: http://www.isaserver.org/pages/newsletter.asp
ISA Server FAQ: http://www.isaserver.org/pages/larticle.asp?type=FAQ
------------------------------------------------------
Other Internet Software Marketing Sites:
World of Windows Networking: http://www.windowsnetworking.com
Leading Network Software Directory: http://www.serverfiles.com
No.1 Exchange Server Resource Site: http://www.msexchange.org
Windows Security Resource Site: http://www.windowsecurity.com/
Network Security Library: http://www.secinf.net/
Windows 2000/NT Fax Solutions: http://www.ntfaxfaq.com
------------------------------------------------------
You are currently subscribed to this ISAserver.org Discussion List as:
tshinder@xxxxxxxxxxxxxxxxxx
To unsubscribe visit http://www.webelists.com/cgi/lyris.pl?enter=isalist
Report abuse to listadmin@xxxxxxxxxxxxx


Other related posts: