unknown workgroups/domains in our network

Please help, when I browse to My Network Places|Entire Network|Microsoft Windows Network I can see my domain. The problem is that other domains or workgroups periodically appear as though someone has plugged in to our network. For instance, today I can see Alfeld, Dky and Wilmar. We don't have WiFi. Can anyone please tell me if there is any way to find out where this Workgroup/Domain is coming from? and how to block them? Thank you in advance.
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d_williaConnect With a Mentor Commented:
As Yaniv said, checking your DHCP server for unknown stations is a good start.  If you have a WINS server, it will show you exactly what devices are advertising what workgroups as long as they are configured to use WINS.
Failing those suggestions, there are a couple packet sniffers out there that can sniff for NBT Traffic.  Go to www.ethereal.com or www.wireshark.org and download either one.  Run it on a computer that can see these rogue workgroups.  After a few minutes, you should have a good sample to parse through to find the IP addresses of the offenders.
You likely have other computers connected to your network that are not members of your domain, but their own workgroups.  Likely Windows XP Home or earlier machines.
weikiiroAuthor Commented:
Is there any way I can find out what is their IP address or any informations?
Yaniv_HoobianConnect With a Mentor Commented:
Check the DHCP for unknown stations

Yaniv_HoobianConnect With a Mentor Commented:
You can also try using Look@Lan or the newer Fing


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