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PDC & BDC fighting.

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13 replies

by diskfailure

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We have a PDC server running NT4.0 sp6a and a BDC server running NT4.0 sp6a. Workstations are W2K, NT4.0 and 98 mix. Heres the problem. The PDC went down. Software failure. The BDC was promoted to a PDC to run the show while the orginal PDC was rebuilt. Once the origianl PDC was back up and running the BDC " currently acting as a PDC " was demoted back to a BDC and the PDC was brought back on line. Once everything was up and running both the BDC and the PDC lost all user info, and computer info in user mgr and server mgr. Once we realized we couldnt reterive the lost info we re added all workstations and user account. Now that all accounts have been added back we now receive errors from the BDC. These errors are reported everytime a user or PC logs onto the network. The error reads as follows " The computer * tried to connect to the server "BDC that was promoted then demoted" using the trust relationship established by the DOMAIN. However the computer lost the correct SID when the domain was reconfigured. Reestablish the trust. Why do I still get this error? The original PDC is back and the BDC is back to a BDC. What gives?

13 replies

by timwalsh

What software failed on the original PDC? Was it Windows NT? Did you have to reload NT to get it operating again?

If you did a fresh install of NT, then the "PDC" has a new SID that isn't recognized by the rest of the domain. Thus you essentially have a "PDC" in a domain by itself with a "BDC/PDC/BDC" and the rest of the network in what for all intents and purposes is a different domain with the same name. What you should have done was rebuild the server as a BDC, join it to the domain,force synchronization from the BDC-turned-PDC, and promoted the original PDC back to PDC (which would automatically demote the former BDC back to BDC).

If you did a repair install or a repair from backup, you didn't synchronize the domain beforeputting the original PDC back on line. Once the PDC was operational, you should have demoted it to BDC, rejoined it to the domain, forced synchronization from the BDC-turned-PDC, and promoted the original PDC back to PDC (which would automatically demote the former BDC back to BDC).

At this point you might try the following:
1. Take the original PDC offline.
2. Attempt to promote the BDC back to PDC (this may or may not work).
3. Rebuild the old PDC (again) as a BDC.
4. Follow the steps above to rejoin the domain and promote to PDC.

However, with the problems you seem to be having with SIDs, to ensure stability, I would recreate the domain from scratch (as painful as it might be). The only other way out might be if you havea good, full backup of your PDC before it failed. Even with this, you would probably have to recreate the BDC (unless you have a backup of it also) and remove and then rejoin all workstations to synchronize SID references.

Good Luck.

by diskfailure

Thanks, looks like I need to rebuild the BDC to clear up the SID errors. I was brought in on the end of this mess and Im just trying to figure out what happened and why.

by maelgwyn

Have you tried to repromote the BDC and forcingthe PDC to get the information again? Also, does the PDC really need to be a PDC (why not leave the BDC alone :? ). This is why you lost the info - the BDC got the user logs from the PDC (and when they dont exist, they delete them).

by diskfailure

Thanks, that what I though had happened to the user data base. The new PDC ovewrote the old on the BDC. I was brought in on the end of this mess and Im just trying to figure out what happened and why.

by shmaltz

What happened was that you recreated you domain by entering the computer accounts. However does computers didn't yet register on the new domain. Those computers think that they are still registered and they don't know that they have to reregister onthe domain, that's why you are getting those errors.
To work around this problem:
On the servers (pdc/bdc) delete all computer accounts that are for Windows NT/2K machines.
On each NT/2k computer (You don't have to do it on the 9x machines)log onas local Admin, then in the network Identification tab change its membership to workgroup, restart the computer. Logon again with local admin, In network ID tab join the domain give a domain admin name when asked.
This should recreate the accounts for each computer with the correct SID.

by diskfailure

We have removed all workstations from the domain and re-added them to the new DC. However since the original BDC is still there the workstations are still trying to get their SID from it. Looks like I need to rebuild the original BDC Thanks

by michaeltubs

Have a look at the master browser settings on both PCs, make sure that the PDC is the master browser computer which will authenticate all users.

by diskfailure

The PDC is the master browser. I think my problem is with in the rebuild of the PDC and sync of PBC and BDC

by gigelul

Ouch, now you don't have a domain/network.
As in first answer you don't follow the normal steps: with both PDC and BDC online the BDC must be promote to PDC, the old PDC automaticaly is demote to BDC and can be removed from network.
Since you losed the user and computer accounts the best solution is to built again your domain/network:
-install a PDC
-install a BDC
-create user accounts
-authenticate the computers in domain
-make again all previous settings: additional groups, permission access to resources, logon scripts, shares, security policy, etc.

by diskfailure

I have recreated all the user accounts and computer accounts, reset the trust and permissions. I still get SID errors from original BDC. Looks like I need to rebuild the BDC to stop all the errors. Thanks a

by gigelul

Yes, you must rebuilt the BDC. This old BDC was authenticated by the old domain controller (old PDC).

by diskfailure

Thanks, I guess there is no other way around it except to rebuild the BDC. I was brought in on the end of this mess and Im just trying to figure out what happened and why.

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