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Exchange AD access queries RRS feed

  • Question

  • Hello

    We have different AD sites spread across EMEA. Our Exchange servers (2007) are all based in London, but we had AD sites in Paris, Munich, Budapest, Coventry, Berlin as well as London.

    Normally, I can see Event ID 2080 in Exchange saying that it has discovered DC's in the AD site:

    Process MSEXCHANGEADTOPOLOGYSERVICE.EXE (PID=2104). Exchange Active Directory Provider has discovered the following servers with the following characteristics:
    In-Site:
    Lon-DC1
    Lon-DC2
    Lon-DC3
    Out-of-site:
    Mun-DC1
    Mun-DC2

    Some questions:

    1. When it says it has "discovered" these DC's, does it mean that it is actually using them, or merely knows of their presence?

    2. Why does it not show all of the DCs in other AD sites apart from Munich?

    I looked at the AD site links, and

    London-Munich is Cost 30
    London-Budapest is Cost 30

    There are other site links but they have higher cost, will Exchange always base what DC's it uses based on AD site link cost?

    Also, if the London DC's were to go out of service for some reason, what criteria would it use to find and connect to remote DC's?

    Environment: Exchange 2007, AD 2003

    Saturday, November 26, 2011 2:54 PM

Answers

  • On Sat, 26 Nov 2011 14:54:28 +0000, Pancamo wrote:
     
    >We have different AD sites spread across EMEA. Our Exchange servers (2007) are all based in London, but we had AD sites in Paris, Munich, Budapest, Coventry, Berlin as well as London.
    >
    >Normally, I can see Event ID 2080 in Exchange saying that it has discovered DC's in the AD site:
    >
    >Process MSEXCHANGEADTOPOLOGYSERVICE.EXE (PID=2104). Exchange Active Directory Provider has discovered the following servers with the following characteristics: In-Site: Lon-DC1 Lon-DC2 Lon-DC3 Out-of-site: Mun-DC1 Mun-DC2
    >
    >Some questions:
    >
    >1. When it says it has "discovered" these DC's, does it mean that it is actually using them, or merely knows of their presence?
     
    The Global Catalog servers that are "in site" are used by the Exchange
    server. The Domain Controllers may be accessed to retrieve attributes
    that are not present in a GC in the local AD Site.
     
    >2. Why does it not show all of the DCs in other AD sites apart from Munich?
     
    That depends on your DNS and AD. If the DCs, GCs, their various SRV
    records, etc. aren't in the DNS used by the Exchange server then they
    won't be discovered (Exchange just uses the APIs made available by the
    AD to discover the topology). Other AD-specific information must also
    be in all DCs (e.g. the AD sites and subnets).
     
    >I looked at the AD site links, and
    >
    >London-Munich is Cost 30 London-Budapest is Cost 30
    >
    >There are other site links but they have higher cost, will Exchange always base what DC's it uses based on AD site link cost?
     
    The cost of the AD site links is only relevant if your sending e-mail
    between servers in those AD sites (or looking for Public Folders).
    Once Exchange has to look outside it's own site for GCs it's whichever
    ones respond the fastest that are used.
     
    >Also, if the London DC's were to go out of service for some reason, what criteria would it use to find and connect to remote DC's?
     
    Exchange has no preferences outside its own AD Site.
     
    ---
    Rich Matheisen
    MCSE+I, Exchange MVP
     

    --- Rich Matheisen MCSE+I, Exchange MVP
    Saturday, November 26, 2011 4:18 PM