Host name resolution

How are host names determined?

The network scan results list shows the incorrect names for most (all?) of my hosts and no name at all for others.

For example, I have a host computer running Windows 7. IP Config on it identifies the IP as 192.168.100.105, MAC address xx-xx-xx-xx-xx. The host name shown in Computer Properties is TUC0328. DHCP on my primary domain controller lists all of this correctly. But, Network Scanner shows host TUC0328 is on port 192.168.100.140 with MAC address yy-yy-yy-yy-yy-yy.

Meanwhile, network scanner shows an entirely different device on port 192.168.100.105 / MAC zz-zz-zz-zz-zz-zz; a device which, according to DHCP is actually on 192.168.100.92.

I am very confused.

Firstly, host name resolution is firstly done via a standard system call gethostbyaddr that performs reverse lookups. Unfortunately its behavior is not clearly explained by Microsoft and we don't know where exactly it obtains this information from.

Secondly, if the above fails, it attempts to lookup a NetBios name, similar to how nbtstat works. So normally you should check what these commands return:

1. nslookup -type=ptr x.x.x.x
2. nbtstat -A x.x.x.x
3. tracert x.x.x.x

You can launch these in a command prompt and replace x.x.x.x with the IP address in question.

Thanks again, Andrew.

Do you have any idea what it means if nbtstat returns the correct host name, but nslookup and tracert both return the wrong host name? And how to fix?

Following up, I am looking at my domain controller's DNS Manager, Forward Lookup Zones, [mydomain].local and see a number of conflicting Host(A) records.

I believe I can just delete the entire list and that will cause it to rebuild. Yes?

As nslookup and probably tracert query your DNS server, it's most likely erroneous records in the DNS DB. I am afraid I can't advise on how to fix it though, in absence of any knowledge about your network.

I notice a lot of missing host names too. Do you know if there's a way to get more of them?

There is no one-size-fits-all solution. You may want to setup your own DNS server and assign names to those devices. Otherwise I am afraid there's no magic way to get the names.