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Network Name Resolution Problem NetBIOS?

By Steve Penn ·
I have an annoying problem.

I'm using FPinger to try and draw the network. It basically pings each IP and if it gets a reply it draws a little computer for you.

The problem is that it is missing some machines.

After further investigation it seems that the ones it has problems I cannot do a ping -a to resolve the name against the IP. This is probably why FPinger is missing it.

I think this is a NetBIOS thing but am not sure. How can I
a) get the ping -a to work for all machines.
b) auto search all machines on the network.

Any ideas/suggestions would be most welcome.

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Network Name Resolution Problem NetBIOS?

by Joseph Moore In reply to Network Name Resolution P ...

The -a switch for PING will use DNS for name resolution first. After that, it goes the WINS route (checking a WINS server). Lastly, if it has not been successful, it will look for a NetBIOS <00> record.
If it can't find anything after all this, it will not report any name.
Now, I take it you are not running your own internal DNS server? Doesn't sound like it.
Are the machines that cannot be resolved Windows machines? If they are, try this. Open a Command Prompt and type in:

nbtstat -A IP_ADDRESS_OF_REMOTE_SYSTEM

If all is well, you will get something like this:

Local Area Connection:
Node IpAddress: [10.1.xxx.xxx] Scope Id: []

NetBIOS Remote Machine Name Table

Name Type Status---------------------------------------------
LAPTOP <00> UNIQUE Registered
WORKGROUP <00> GROUP Registered
LAPTOP <03> UNIQUE Registered
LAPTOP <20> UNIQUE Registered
WORKGROUP <1E> GROUP Registered
JOEY <03> UNIQUE Registered

MAC Address = 00-00-00-00-00-00


This is the NetBIOS table on my laptop that is sitting next to me. The <00> Unique record is the name of my laptop (called, ironically enough, LAPTOP).
(This info is NOT in a DNS server or a WINS server, BTW)

Now, when I do a PING -a against its IP address, I get:

Pinging LAPTOP [10.1.xxx.xxx] with 32 bytes of data:

Reply from 10.1.xxx.xxx: bytes=32 time<10ms TTL=128
Reply from 10.1.xxx.xxx: bytes=32 time<10ms TTL=128
Reply from 10.1.xxx.xxx: bytes=32 time<10ms TTL=128
Reply from 10.1.xxx.xxx: bytes=32 time<10ms TTL=128

Ping statistics for 10.1.xxx.xxx:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms

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Network Name Resolution Problem NetBIOS?

by Joseph Moore In reply to Network Name Resolution P ...

Now, the whole point of all this is that there are several reasons why the name resolution could be prevented.
If any of the machines are running a software-based firewall (like ZoneAlarm), that could do it. Either the ICMP Echo packet (the PING) could be blocked, or they could block outbound NetBIOS name requests.
Also, if the machines are on a screen segment (a firewall between you and them) that could also explain it.
Next, if the Windows machines are not running the Workstation service,then that would also do it.
And the last thing I can think of is if the machines do NOT run File and Print Services for Microsoft Networks on their network cards, then that would also explain it.
(there could also be one more reason involving an advanced user right, but let this be the last-ditch possibility).

Anyway, check out those machines and see which suggestion it could be.

And if you want a good network charting program, get NetworkView:
www.networkview.com

hope this helps

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Network Name Resolution Problem NetBIOS?

by Steve Penn In reply to Network Name Resolution P ...

FAO J.Moore

I tried the nbtstat -A and it says "host not found"

no firewalls etc it's all in the internal trusted zone.

the machines are either NT/2K or print servers.

finally workstation is running and it is in the WINS database as wellas in my local NetBIOS cache.

very bizarre - still getting nowhere.

thanx for the info however.

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