Authentification mystery - XP Pro SP3 + Vista Ult 64 SP1

[TT]

I hope I don't post a problem already discussed a hundred times here. I've
found a lot of similar entries, but none seemed to solve my problem, thus
this post.

Basics:
* A little network with 3 computers -- 2x XP Pro SP3, 1x Vista Ult 64.
* Same workgroup name on all computers
* Different computer names for all three
* Different static IP addresses for all three (192.168.178.xy / 255.255.255.0)
* Same username and password for admin on all computers
* Advanced file sharing on XP machines turned on
* NTLMv2 authentification turned on on all three computers
* Private network and sharing turned on on Vista
* Explicit shares on the XP machines with complete rights for everyone
* File and printer sharing for local network turned on on all three machines
* A Fritzbox router with static IP 192.168.178.1


Sit:
* Internet access runs fine from all three computers
* ping runs fine from each computer to the other two and the router
* File sharing runs fine from the XP machines to Vista; i.e., no problem to
access files on the computer running Vista64 from the XP machines -- this
even holds true when I connect to e.g. \\Vista\C$ which shouldn't even exist
any more as far as I got it
* File sharing runs fine from XP to XP
* File sharing does not work from Vista to XP; i.e., when trying to access a
share on one of the XP computers from Vista64 while being logged in as an
admin with the same username and password as on the XP machine, I get a
dialogue asking me for username and password -- and when entering those same
values again it keeps telling me that authentification failed.

This holds true when I try to list the network content on the Vista64
machine -- the XP machines are shown, but every attempt to even only list the
shares produces this ever failing username password dialogue.

Funny enough this problem arouse AFTER INSTALLING VISTA SP1 -- beforehand
accessing XP shares from Vista64 went fine even in the form \\XPa\C$ --
although that shouldn't be allowed any more in Vista as far as I've got it.

Btw -- when trying to apply the LLTD patch on the XP machines it told me it
is older than XP SP3 and doesn't need to be applied. So that shouldn't be the
cause, too. And after all the machines are perfectly visible and can be
perfectly pinged, only any access failes due to the described
authentification error.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Sorry again if this is a repost of a long solved problem and I'm simply too
blind to find the solution that applies to my case. In any case I'd
appreciate any suggestion that helps clear the situation.

Sincerely,

Therese

 

[Mick Murphy]

Have you tried running the Network wizard in XP?

Also, run the XP’s Home or Small Office Network File and Printer Sharing
Wizard to include Vista in your “New†Network, even if you had an XP Network
set up prior to adding a Vista computer to it(redoing the Wizard seems to
work for XP machines!).

In “My Network Placesâ€: “Set up a Home or Small Office Networkâ€
OR under Accessories > Communications > Network Setup Wizard > Allow File
and Printer Sharing.

 

[TT]

Dear Mick,

thanks. I just tried it (without big hope) to no avail. The XPs are
perfectly visible, but login is impossible due to an alleged
username/password mismatch that remains popping up with every single account
set up on the XP machines.

As already mentioned the problem came up **after installing Vista SP1**,
before everything went fine and I could access my XP drives from the Vista
machine.

Afterwards connection to both XPs fails with the same error, whereas the XP
to XP interconnection is still perfectly fine.

Funny enough I can access the XP machines via VNC w/o problems -- which uses
a different authentification and encryption method.

My suspection in the meantime is that with Vista SP1 something changed in
the encryption algorithm used for authentification and thus makes a login on
XP machines virtually impossible at least for me. On the other hand I've
heard of guys who have no problem accessing their XP comps from Vista even
after SP1, thus I'm really facing a riddle right now. If I'm doing something
wrong, then what the heck is it?

Sincerely,

Therese

 

[TT]

Addition:

I just tried to connect to a password protected NAS I received today from
the Vista machine -- and it works.

I don't know exactly which encryption algorithm is used there; it's a MRT
Dual Giga NAS based on a Linux 2.6 kernel.

 

[TT]

Uuups -- after several weeks I finally found two small registry patches that
solved the problem thanks to the hints on PChuck's Network:

(a) (That's possible the most important one when using fixed IPs) Got to

HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Control \ Lsa \

There you either find or have to create "LMCompatibilityLevel" as REG_DWORD.

Enter 1 as value on all computers in your network. That instructs your
computer to use NTLMv2, where possible, but to also accept older auth methods.


(b) (Important if you use a DHCP server to assign the IP addresses of your
workstations) Got to:
HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ Tcpip \
Parameters \ Interfaces \ {GUID}

(where {GUID} means your active network card, just bwrowse through your few
entries till you got it)

There you either find or have to create "DhcpConnForceBroadcastFlag" as
REG_DWORD

Enter a value of 0 -- this way Vista does not use DHCP broadcast if your
router doesn't support it.


After a restart I could connect to my XP Pro SP3 workstations again.

Sincerely,

Therese