Join Log in
Score:0
Cody Konior avatar Server

Can any local domain controller authenticate NTLM or do they pass it on to the primary domain controller?

in flag
Cody Konior

When a Windows server needs to authenticate a domain user with NTLM it asks the local domain controller.

My question is whether that domain controller (assuming the user is in that domain) can process NTLM authentication entirely locally, OR, does it have to forward the request to the primary domain controller to do part of the authentication?

I would have assumed it does it entirely locally but NTLM has been around since NT 4 and the PDC carries PDC Emulator responsibilities. Furthermore DCs are meant to be in constant contact with the PDC otherwise weird things can happen, but that weirdness is not well defined.

The reason I ask is to determine whether specific authentication issues between servers and a DC (that I won't go into here) could be influenced by WAN failures between the DC and the PDC.

Thanks.

75
1 + 3
Semicolon avatar
jo flag
Semicolon
DCs are not required to be in constant contact with the PDC. The weirdness is well defined. One can (or should be able to) identify which FSMO role is unavailable based upon which symptoms. Have you looked at what the PDCe FSMO role "responsibilities" are? If there are logon failures at remote sites because of lack of connectivity, I would first look to ensure that all WAN sites have Global Catalog servers present or alternatively that Universal Group Membership Caching is enabled for that site. In a multi-domain environment, logons can't proceed without connectivity to either of those
0
Reply
Semicolon avatar
jo flag
Semicolon
PDCe FSMO role holder is responsible for 1) Source of time for other Domain controllers in a domain (by default), 2) Being preferentially notified of password changes, 3) being double-checked if a password fails at any other domain controller, because of that 4) processing all account lockouts, 5) runs the SDProp process, 7) preferred connection point for Group Policy Management Console, there may be one or two other, but they're generally trivial.
0
Reply
Semicolon avatar
jo flag
Semicolon
Also, if at all possible, avoid NTLM (certainly v1).
0
Reply
Score:0
tsc_chazz avatar Server
vn flag
tsc_chazz

I can't claim exhaustive knowledge, but the idea of a primary domain controller sort of faded with Windows 2000. Starting with Windows 2000, the DCs are meant to be basically peers, although there will be single authoritative servers for the various FSMO roles. (The databases used are meant to replicate to all DCs, but in case of conflict one is nominated as the role holder.) So to answer your question, the authentication does come from whichever DC was actually contacted first, no reference back to the authoritative role holder is required or made; but if the authoritative role holder is out of contact due to WAN issues for a long time, the various DCs can fall out of sync with each other resulting in the odd situation you're hinting at.

0 + 0
ธงชาติไทย
Elon Musk
I sit in a Tesla and translated this thread with Ai:

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.