2009-06-27

๑ Simple ideas to help identify devices on a network

I will begin this post by recommending the Solarwinds free tool IP Address Tracker that helps you to scan, track, and consolidate your IP address network information in one easy place.

On a medium sized network, some devices may not present you much information, and when in doubt about a particular ip address you can see if port #139 (netbios-ssn) is opened using a very neat app called NetBrute.

If it is, probably it is a computer and is sharing it's local resources, folders and printers over the network. For further inspection, you can try this address on your windows explorer address bar:

\\ipadress\c$

If you have domain administrator rights and that ip address is on your domain you can check what users are using that computer via C:\documents and settings\ folder.

If that doesn't work probably port 139 is closed, and it may be a printer device. Usually tough, printers configuration page is set trough http service so port #80 should be opened and http:\\idadress should lead you to that configuration page where you can see the printers name.

.Usually large printers however have another way to communicate their info trough the SNMP protocol. There are SNMP explorer apps out there that basically scan your network using a community string to fetch information about the various SNMP devices present on your network. Solarwinds for instance provides such tools.

.SNMP is not present in printers only, Cisco Switches, routers, hubs and bridges also use SNMP protocol to show and manage network information. SNMP is A MUST to obtain immediate states from your devices, for instance, if you want to see if the printer is printing anything in that right instance SNMP is the protocol to communicate to. I'm planning on writing a simple article about SNMP soon, demystifying it, as in general info. about SNMP is somehow mystified, i think.

Another protocol of interest, or maybe i should say service in this case, is the windows management instrumentation (WMI) that computer systems with windows operating systems from Windows NT 4.0 SP4 forward have, is a great tool to send information about computers using WMI Classes.

Thanks for reading

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