Miscommunication through CISCO routers after migration from Win NT to Win 2003

Posted on 2006-03-30
Last Modified: 2010-04-09
Dear Sirs,

After upgrading a domain from Win NT to Win 2003 all the client computers from the subnets are unable to log on to the domain. The clients on the same network segment as the Domain Controller have no problems. All the communication to/from the other segments passes through the following CISCO routers: 7200vxr and 2600.

TCP-IP is traffic is not affected.

Any idea what protocols and TCP/UDP ports should be allowed for proper communication and authentication?

Question by:Menshen
    LVL 79

    Expert Comment

    Win2003 domain is 100% dependent on properly configured DNS and having the clients auto-register themselves in DNS just like they did with WINS. Clients must point to this internal DNS server as primary in order to find the server, and the SRV records must be there.

    You might want to setup a WINS server at least temporarily if all of your client workstations are not up to XP..
    LVL 51

    Expert Comment

    by:Keith Alabaster
    Has anything else changed in your setup?
    By tcpip traffic, I assume that you can ping by ip address and name to the domain server(s).
    Are any dhcp-set work stations on the associated subnets picking up the correct settings such as IP, mask, gateway, dns servers?

    Author Comment


    We solved the problem thanks. DNS and WINS were always available.
    We realized we had to change the MTU size on the router... I guess AD authentication in 2003 R2 is more sensitive to changes on the packets.
    LVL 79

    Expert Comment

    What kind of communications lines do you have, and what did you have to change the MTU size to ?

    thanks for the update!

    Accepted Solution

    PAQed with points refunded (450)

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