Same IP, multiple A entries within DNS, tied to multiple hostnames.

Posted on 2007-08-06
Last Modified: 2013-11-25
Hi Guys...
I am in a bit of a fix. Two machines are replying with the same IP address but different hostnames. No, none of them is multihomed!!

I have both DNS and WINS enabled on my network.

Here's what exactly happens on my Windows 2003 AD network:
C:\Documents and Settings\f.s>ping ABC
Pinging [] with 32 bytes of data:
Reply from bytes=32 time<1ms TTL=127
Reply from bytes=32 time<1ms TTL=127
Reply from bytes=32 time<1ms TTL=127
Reply from bytes=32 time<1ms TTL=127

Then I give the command:

C:\Documents and Settings\f.s>nbtstat -a
Local Area Connection 3:
Node IpAddress: [] Scope Id: []

NetBIOS Remote Machine Name Table

Name Type Status
XYZ <00> UNIQUE Registered
PCDOMAIN <00> GROUP Registered
XYZ <20> UNIQUE Registered
PCDOMAIN <1E> GROUP Registered

MAC Address = 00-04-75-E3-A4-1C

C:\Documents and Settings\f.s>ping xyz

Pinging [] with 32 bytes of data:

Reply from bytes=32 time<1ms TTL=127
Reply from bytes=32 time<1ms TTL=127
Reply from bytes=32 time<1ms TTL=127
Reply from bytes=32 time<1ms TTL=127


I have confirmed that machine doesn't physically exist on my network, only machine xyz does.

Both the machines, ABC adn XYZ have an 'A' entry on my DNS server.

So, why and how does this entry of ABC come from? My IP addresses are dynamically allocated but then why is DNS/WINS keeping some old entries?

Any clues??
Question by:fahim
    LVL 31

    Expert Comment

    make on both machines and on your dns server a
    ipconfig /flushdns
    ipconfig /registerdns
    LVL 70

    Expert Comment

    It would also be a good idea to enable aging and scavenging which will automatically clear out stale DNS entries

    Author Comment

    I was wondering, if WINS plays any role in this? Can I safely turn off my WINS? I have no pre-windows 2000 machines on my network.

    Pls advise!!
    LVL 10

    Expert Comment

    by:Walter Padrón
    Yes, it could be a record in WINS database.

    Some services still rely on WINS for function or for some partial functionality but generally you can disable WINS if you have DNS + dynamic updates enabled. We disabled it long time ago.


    LVL 5

    Accepted Solution

    I dont think wins has anything to do with this - it just looks like you have an incorrect record in DNS. just use the DNS MMC to delete the record. If it comes back then either something is registering the record in DNS or perhaps the DNS database it out of sync. If after deleting the record it reappears have a look at the owner under security tab - may help to find out whos registering the record. Check the DNS database version is consistent across all DNS servers (it has a serial number in the soa record). Once you get it working its a good idea to set up scavenging as KCTS says or possibly if using DHCP get the DHCP server to register all records (although there are some security concerns).
    Should be no problem switching off wins (stop the service on all WINS server and see what happens).
    LVL 51

    Expert Comment

    by:Keith Alabaster
    cmptrwhiz - I have now placed a member comment in your profile. Please take the time to read and digest its comments. You can find it here at the very bottom of the page.

    Thank you

    Networking Zones Advisor

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