Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations Mike Lewis on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
PDC
- Thread starter people2
- Start date
tekinfarmland
Technical User
Ok, I take a shot. It has been a while since I dealt with the stuff, and I don't live in the text books, so....
A PDC and a BDC a primarily the same, both manage security and resources in the domain, with the exception that BDC is the backup. A BDC only becomes active when it is promoted to a PDC status. Also the PDC usually is the "master browser" for the domain, keeping track of the netbios stuff.
To answer the first question: A BDC is the same, but non-active. It receives the same updates from the domain, put on a replicated cycle. (don't ask me what that timing is, I can't remember the text book answer. If I had to guess, it is something like every 15 minutes).
Answer for the Second Question: If the BDC isn't promoted and the PDC is offline, Some user may not be able to login to some network resources. Based on cached profiles, etc, some users may "look" like they logged into the windows desktop, but not really (it may give them something like 'domain controller not found'). Anyone using that domain to authenticate to a network share, folder or website, will probably be denied access without much of an explanational error message.
Tekinfarmland
A PDC and a BDC a primarily the same, both manage security and resources in the domain, with the exception that BDC is the backup. A BDC only becomes active when it is promoted to a PDC status. Also the PDC usually is the "master browser" for the domain, keeping track of the netbios stuff.
To answer the first question: A BDC is the same, but non-active. It receives the same updates from the domain, put on a replicated cycle. (don't ask me what that timing is, I can't remember the text book answer. If I had to guess, it is something like every 15 minutes).
Answer for the Second Question: If the BDC isn't promoted and the PDC is offline, Some user may not be able to login to some network resources. Based on cached profiles, etc, some users may "look" like they logged into the windows desktop, but not really (it may give them something like 'domain controller not found'). Anyone using that domain to authenticate to a network share, folder or website, will probably be denied access without much of an explanational error message.
Tekinfarmland
JMcAllister
MIS
Changes to the SAM are handled by the PDC, then replicated to the BDCs. If the PDC is offline and a BDC is not promoted, users will not be able to change their passwords, among other things.
HerbRoach52
IS-IT--Management
Prior responses are correct, and to add to them....
When you have multiple servers on a LAN or WAN for that fact there are 'elections' that go on every X amount of minutes. If your SAM and WINS tables aren't healthy there is a possibilty the PDC will be demoted and a BDC will promote itself. This of course is a problem and can servely misconstrue the forementioned tables and the table many admins forget to mention, the ARP table. This table talks to the router and if this table becomes corrupt the user will not hit the internet either. Also, if you have a mixed node LAN of servers (2000/NT) make sure the 2000 servers are standalone and not BDC's. If an election is made the 2000 server will win the battle and then you really have a problem...if anyone knows about a 2000 PDC then you know what i mean...
...the higher the fewer...
When you have multiple servers on a LAN or WAN for that fact there are 'elections' that go on every X amount of minutes. If your SAM and WINS tables aren't healthy there is a possibilty the PDC will be demoted and a BDC will promote itself. This of course is a problem and can servely misconstrue the forementioned tables and the table many admins forget to mention, the ARP table. This table talks to the router and if this table becomes corrupt the user will not hit the internet either. Also, if you have a mixed node LAN of servers (2000/NT) make sure the 2000 servers are standalone and not BDC's. If an election is made the 2000 server will win the battle and then you really have a problem...if anyone knows about a 2000 PDC then you know what i mean...
...the higher the fewer...
Actually.. a BDC can act as load balancer for the PDC should authentication requests become too much ... it is a keeper of the SAM database.. but the PDC is the King which holds the original.
If the PDC goes down... the BDC will provide authentication -- only it will be very slow -- because it will first defer authentication requests to the PDC for verification.. should it NOT find the PDC.. it will search its own SAM.. (usually a replica of the PDc's SAM), and will authenticate at that time.
IF the BDC is THE WINS server of the network... NetBIOS resolution will continue as it would whether the PDC is up or down.. but the PDC is the Main Browser Server .. therefore .. resolution may be slower. Which is why it is always best to promote the BDC once the PDC kacks! It will become the main browser server.
Alshrim
System Administrator
MCSE, MCP+Internet
If the PDC goes down... the BDC will provide authentication -- only it will be very slow -- because it will first defer authentication requests to the PDC for verification.. should it NOT find the PDC.. it will search its own SAM.. (usually a replica of the PDc's SAM), and will authenticate at that time.
IF the BDC is THE WINS server of the network... NetBIOS resolution will continue as it would whether the PDC is up or down.. but the PDC is the Main Browser Server .. therefore .. resolution may be slower. Which is why it is always best to promote the BDC once the PDC kacks! It will become the main browser server.
Alshrim
System Administrator
MCSE, MCP+Internet
- Status
Similar threads
- Locked
- Question
- Locked
- Question
- Locked
- Question