Hi,
I am new to Active Directory and I was reading about having a DC on each
site could help speeding up the authentication.

My question is if users on different sites need to log in to a web based
application running at the central office, then if DC on each site would help
speeding up authentication, or web based apps and IIS use different way for
login process?

If the question appears to be confusing, please let me know and I'll try to
explain it in a more detailed fashion.

Thank you very much.

Coady,

I will address only the 'DC in each Site' part of the question.

Yes, you are correct.  It is generally a really good idea to have a Domain
Controller in each Site.  And, to make sure that this Domain Controller is
also a Global Catalog Server.

Let's look at an example:

You have a nice company that has locations in three locations: Los Angeles,
New York and Miami.  It is all one domain: yourdomain.com.  You have created
the three Sites in Active Directory Sites and Services (er, well you created
two and renamed the one that already exists).  You create the Subnets and
associated each Subnet to the correct Site.  You also created the Site
Links.

So, you have two Domain Controllers in each Site.  In LA you have LAX-DC01
and LAX-DC02.  In New York you have NYC-DC01 and NYC-DC02.  In Miami you
have MIA-DC01 and MIA-DC02.

Why do you create Sites?  To do two things: to assist in user logons and to
control Active Directory replication.  We will look at the logon part of
that.

You clearly do not want your users in Miami to authenticate against a Domain
Controller in Los Angeles or in New York.  You want them to authenticate
against a 'local' Domain Controller.  So, you create the Sites and Subnets
and put the Domain Controllers in the correct Site and everything is
supposed to work out just swell.  This does not always work that way,
though.  In WIN2000 there were some problems.  However, in WIN2003 this area
has been greatly improved (well, so I have read!).  I would suggest that you
take a look at the Branch Office Deployment Guide.  This should really help
this part of the question.

Here are two articles that might help things:

http://support.microsoft.com/?id=247811
http://support.microsoft.com/?id=314861

I will leave the IIS part to someone who actually knows what they are
talking about in that area.  You would get nothing but gibberish from me!
Well, I am sure that there are those who would contend that I am very good
at dispensing with the gibberish!

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