Solved

Netbios-NS packet capture

Posted on 2011-02-16
6
1,432 Views
Last Modified: 2012-05-11
I am using Wireshark to capture network traffic from an Windows XP workstation that makes an HTTPS conection to a remote host.   In the packet capture I can see Netbios name query broadcasts to the remote host.  I was hoping the packet capture would also show me what name the query was being performed against but the packet just shows zeros.   Is there a way for me to determine what name was queried?

Capture.PNG
0
Comment
Question by:AManoux
  • 4
  • 2
6 Comments
 
LVL 12

Accepted Solution

by:
Sommerblink earned 250 total points
Comment Utility
Well.

The fact that you see NetBIOS queries going from the client to the server is telling me that you have a DNS problem.

In the real-world (eg: going to www.google.com, etc), you do not rely on NetBIOS for any name resolution.

Typically, when Windows (especially any version of windows which is still actively supported by Microsoft) resorts to NetBIOS for name resolution... it means that your client has no other way to resolve the name. (Please see http://www.microsoft.com/downloads/en/details.aspx?FamilyID=c76296fd-61c9-4079-a0bb-582bca4a846f, chapter 7)

So, besides the fact that you are seeing a NetBIOS packet while attempting to go to a website, what else is wrong?
0
 
LVL 1

Author Comment

by:AManoux
Comment Utility
Thanks Sommerblink.
I agree, I have a feeling there is a DNS issue going on but I don't know where to start troubleshooting without knowing what host name the XP machine is having trouble with.  If I can't find out the host name via the Netbios request, how else can I determine it?
Everything is functioning with the HTTPS request to the website and the website page being accessed.  It just hangs for 3-5 seconds while the Netbios name lookup occurs and then times out.  
0
 
LVL 1

Author Comment

by:AManoux
Comment Utility
Attaching more of the Wireshark capture for added information
Capture2.PNG
0
Highfive Gives IT Their Time Back

Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

 
LVL 12

Expert Comment

by:Sommerblink
Comment Utility
Sorry for the delay.

Anyway, you can try to simply disable NetBIOS on that network card / network connection (if its VPN or whatnot).

Simply go to the network card / network connection, go to properties, IPv4 properties, then go to the advanced button.

On the WINS tab, place a radio dot next to Disable NetBIOS over TCP/IP.

Let see if this makes your queries go away without breaking anything else.

If it does, then at least you've got some new information.
0
 
LVL 1

Assisted Solution

by:AManoux
AManoux earned 0 total points
Comment Utility
Thanks for getting back to me.  Sine my last post I belive I've discovered the cause of the issue.
Client SSL implementations often try to reverse DNS lookup the IP of the connection to try and validate the DN of the certificate presented during the SSL handshake.  Because there was no PTR DNS record for the hostname my client dropped back to using Netbios broadcasts. The lack of the PTR record didn't stop the SSL connection from occuring, it just slowed it down at the beginning while it tried to resolve the certificate host name.  
0
 
LVL 1

Author Closing Comment

by:AManoux
Comment Utility
Solved my own issue
0

Featured Post

How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

Join & Write a Comment

Large and small networks have one same need, Service monitoring. Service monitoring consists of watch services of the several servers in the network. To monitor means that the administrator will receive an alert when a service is down or it's state …
Enterprise networks where VoIP phones have been deployed frequently use port configurations that allow both a computer and an IP phone to be plugged into the same switch port but use different VLANs. On Cisco equipment I'm referring to the "native V…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

728 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

9 Experts available now in Live!

Get 1:1 Help Now