First, try using NSlookup to check that you resolve A and SRV records :
http://social.technet.microsoft.com/wiki/contents/articles/29184.nslookup-for-beginners.aspx
http://support.microsoft.com/kb/241515

You can also check that your DCs are IP settings are well configured. You can find my recommendations here: http://www.ahmedmalek.com/web/fr/articles.asp?artid=24

DNS registration of your DCs can be forced by running ipconfig /registerdns and by restarting netlogon service.

C:\Users\peter>nslookup
DNS request timed out.
    timeout was 2 seconds.
Default Server:  UnKnown
Address:  192.255.10.21

> tst220750a.com
Server:  UnKnown
Address:  192.255.10.21

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
Name:    tst220750a.com
Addresses:  2002:c0ff:a15::c0ff:a15
          192.255.10.21

C:\Users\peter>ipconfig /registerdns

Windows IP Configuration

Registration of the DNS resource records for all adapters of this computer has b
een initiated. Any errors will be reported in the Event Viewer in 15 minutes.

Hi,
Thanks a lot.

I run this

C:\Users\peter>nslookup
DNS request timed out.
    timeout was 2 seconds.
Default Server:  UnKnown
Address:  192.255.10.21

> tst220750a.com
Server:  UnKnown
Address:  192.255.10.21

DNS request timed out.
    timeout was 2 seconds.
DNS request timed out.
    timeout was 2 seconds.
Name:    tst220750a.com
Addresses:  2002:c0ff:a15::c0ff:a15
          192.255.10.21

and have restarted Netlogon service on server,

and also have run this

C:\Users\peter>ipconfig /registerdns

Windows IP Configuration

Registration of the DNS resource records for all adapters of this computer has b
een initiated. Any errors will be reported in the Event Viewer in 15 minutes.

but I still get this

Hello

check c:\windows\debug\netsetup.log

Have you checked also the SRV record? Please manually remove the registered IPv6 IP address for the DC and

Hello

192.255.10.21 it public ip.

not 192.168.10.xxx ?

Hello

Add ipconfig -all from your domain controller please.

Can I have more details to your advice?

Any other advice?

Hello

to join domain need internal domain name not public domain name.
so need to login to Domain controller and check ip settings. you need list DC ip settings and search internal ip address like 10.0.0.0 - 10.255.255.255, 172.16.0.0 - 172.31.255.255, 192.168.0.0 - 192.168.255.255
After you have internal ip go to DNS console and check DC A record that ip need internal ip.

Sorry Sneff, how to list out DC IP settings?

Hello

ipconfig -all

Hi,

The reason why we can ping IP address but not host name/domain name is lack of DNS resolution.

Does the IP address 192.255.10.21 belong to Domain Controller? If not, please fill in the Domain Controllers IP address.

Otherwise, we need to make sure that all related SRV records described in the article below are correctly registered on the DNS server you have specified.

How DNS Support for Active Directory Works

https://technet.microsoft.com/en-us/library/cc759550%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396

Best Regards,