Dear all I have 3 dns servers are running windows 2008 Ent., and two exchange server one exchange is running front end and other one is backend (database). The day one I installed the domain and exchange installation time I had only one domain controller later I adder another two domain controllers this three are global catloge servers. My problem now my first domain controller (my first server) dns is down any problems happens my users are not able to use outlook. After a long try it is going to offline…but domain loggin or file server access or internet access no problem. I want a solution any server one of this server is down shouldn’t affect the exchange..especially the first domain controller is not working. Basically user shouldn’t feel that this domain controller is down…please advise me what I am missing this automatic switch over…..

On Sat, 26 Feb 2011 07:31:47 +0000, NIYAS2000 wrote: >I have 3 dns servers are running windows 2008 Ent., and two exchange server one exchange is running front end and other one is backend (database). The day one I installed the domain and exchange installation time I had only one domain controller later I adder another two domain controllers this three are global catloge servers. My problem now my first domain controller (my first server) dns is down any problems happens my users are not able to use outlook. After a long try it is going to offline?but domain loggin or file server access or internet access no problem. > >I want a solution any server one of this server is down shouldn?t affect the exchange..especially the first domain controller is not working. Basically user shouldn?t feel that this domain controller is down?please advise me what I am missing this automatic switch over?.. Exchange should stop using that GC after the toplogy discovery thread sees the server as unreachable. The thread runs every 30 minutes. Restarting the System Attendant service will cause that thread to run, too. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Heloo Rich I am so sorry to say that i didnt get the answer could you plaese explain.. regards NIYAS

On Sun, 27 Feb 2011 06:30:44 +0000, NIYAS2000 wrote: >I am so sorry to say that i didnt get the answer could you plaese explain.. Exchange uses the results if the topology discovery to know what GCs are in "in site". If it's using the GC that's become inoperable it will continue to use that one until it's reported as no longer operable. The toplogy discovery thread runs every 30 minutes but you can force it to run immediately by restarting the System Attendant serive. The out-of-service GC shold be reported as "unreachabe" and Exchange will switch to using on that's "reachable". --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

HI: In theory, Exchange will discover another DC for 10-15 minutes. In reality it can take 35 minutes before Exchange settles if you don't force it to use a specific domain controller. Exchange doesn't use multiple domain controllers. It only uses one. That is why you can only specify one domain controller in the Manage Configuration Domain controller. Therefore it is unlikely to work in the way that you have thought.

Hello I have doubt..in large enviornement let us take an example 1000 users in a single active directory, thier domain is running widnows 2008 R2 Ent edition, in this lan 5 Active directory servers this all 5 dc are acting as global catlog server as well, in this domain they have one exchange server, now my question is if one of the domain controller is down user shouldnt feel that one server is down. in your answers you are telling that topology discovery it will run every 30 minutes or 10-15 minutes...still this 10-15 minutes is too much...in a production enviornment, ok is it ways to automate this facility?... how can i do this switch over manually here it is i am attaching screen print of my exchange server's global catlog servers list. Here if my first GC (ZOSCODC01) server is down all my users are not able to use. In my case how can i solve this issue if any ciscumstances my first server is down how can i manage this ......... i want to setup the things automaticaly, Thank you very much all your support time and reading my threts. http://cid-967db7bd9b3ae474.office.live.com/browse.aspx/.Public/exchange%20server%202007?uc=1 regards, NIYAS

It is the way to modify dc manually. http://technet.microsoft.com/en-us/library/bb691055(EXCHG.80).aspx Rich also mentions that “The toplogy discovery thread runs every 30 minutes but you can force.it to run immediately by restarting the System Attendant serive.” But all these two ways are impossible to be finished in 10 minutes. So…

Hello Terence Thank you very much for your replay.... I have a doubt then what is the point having more than one deomain cotrollers....?? If exchange will look always the first DC then useless having morethatn two domain controllers... Then what will do the big organisations which they have more than 5000 users they are located in diffrent plasces of the world.....eg: GE they plenty of users are located diffrent part of the world and they have lot of servers dc and exchange servers....what they will do their first dc went down... i feel that it is draw back of microsoft... Thank you to all who spend time here to read and write your valuable answers... Bye NIYAS