• Twitter
  • FaceBook

Exchange Server Forums

Forums | Register | Login | My Profile | Inbox | RSS RSS icon | My Subscription | My Forums | Address Book | Member List | Search | FAQ | Ticket List | Log Out

Exchange 2010 AD Topology Discovery Failed

Users viewing this topic: none

Logged in as: Guest
  Printable Version
All Forums >> [Microsoft Exchange 2010] >> General >> Exchange 2010 AD Topology Discovery Failed Page: [1]
Message << Older Topic   Newer Topic >>
Exchange 2010 AD Topology Discovery Failed - 17.Sep.2012 2:23:55 AM   


Posts: 2
Joined: 17.Sep.2012
Status: offline
Approximately every 3 days, Exchange loses contact with all the domain controllers and fails. The only way to resolve the issue is to restart the server. Once restarted, it functions perfectly with clean event logs right up until the next failure. I've been working on this for around 4 weeks now, since the problem began, but I am unable to find the root cause. I am also unable to tie the start of these problems with any particular change to the configuration of the network.

We have 2 x 2008R2 domain controllers and a domain running at 2008R2 functional level. Exchange 2010 is also installed on Server 2008R2, and all three of these servers are virtualised on VMWare ESXi 4.1.


The last good application event log entry looks like this:

Event 2080, MSExchange ADAccess

Process MSEXCHANGEADTOPOLOGYSERVICE.EXE (PID=1992). Exchange Active Directory Provider has discovered the following servers with the following characteristics:
(Server name | Roles | Enabled | Reachability | Synchronized | GC capable | PDC | SACL right | Critical Data | Netlogon | OS Version)
DC01.domain.com CDG 1 7 7 1 0 1 1 7 1
DC02.domain.com CDG 1 7 7 1 0 1 1 7 1

Then an error:

Event 1009, MSExchangeMailSubmission

The Microsoft Exchange Mail Submission service is currently unable to contact any Hub Transport servers in the local Active Directory site. The servers may be too busy to accept new connections at this time.

Another error:

Event 6003, MSExchange SACL Watcher

SACL Watcher servicelet encountered an error while monitoring SACL change.
Got error 1722 opening group policy on system DC01.domain.com in domain domain.com

A warning:

Event 1007, MSExchange Mailbox Replication

The Mailbox Replication service was unable to determine the set of active mailbox databases on a mailbox server.
Mailbox server: EXCHANGE.domain.com
Error: MapiExceptionNetworkError: Unable to make admin interface connection to server. (hr=0x80040115, ec=-2147221227)

An informational event:

Event 2070, MSExchange ADAccess

Process STORE.EXE (PID=5012). Exchange Active Directory Provider lost contact with domain controller . Error was 0x80040951 (LDAP_SERVER_DOWN (Cannot contact the LDAP server)) (). Exchange Active Directory Provider will attempt to reconnect with this domain controller when it is reachable.

An error:

Event 2104, MSExchange ADAccess

Process STORE.EXE (PID=5012). Topology discovery failed due to LDAP_SERVER_DOWN error. This event can occur if one or more domain controllers in local or all domains become unreachable because of network problems. Use the Ping or PathPing command line tools to test network connectivity to local domain controllers. Run the Dcdiag command line tool to test domain controller health.

A warning:

Event 2121, MSExchange ADAccess

Process STORE.EXE (PID=5012). Exchange Active Directory Provider is unable to connect to any domain controller in domain domain.com although DNS was successfully queried for the service location (SRV) resource record used to locate a domain controller for that domain.
The query was for the SRV record for _ldap._tcp.dc._msdcs.domain.com
The following domain controllers were identified by the query:

Meanwhile, the system log shows:

Event 5719, NETLOGON

This computer was not able to set up a secure session with a domain controller in domain DOMAIN due to the following:
The RPC server is unavailable.
This may lead to authentication problems. Make sure that this computer is connected to the network. If the problem persists, please contact your domain administrator.


From this point onwards the event log just fills up with errors and warnings and all the Outlook clients get kicked off. From the Exchange server, via RDP, I can ping both domain controllers no problem.

One other error I am seeing is an SMB error when I try to browse the network from the Exchange server (while it has failed). I get a message: "The name limit for the local computer network adapter card was exceeded". The documentation I have found for this is quite old and the suggested registry key changes for TcpTimedWaitDelay and MaxUserPort are already set as recommended.

Once the server has been restarted, I have little avenue for further investigation as the event logs run clean and everything seems fine. Even when the server fails, everything else on the network functions perfectly and there are no errors in the domain controllers' event logs.

I've been down numerous avenues here, but I'm running out of ideas and I would really really appreciate some help with this problem.

Many thanks in advance,
Post #: 1
RE: Exchange 2010 AD Topology Discovery Failed - 17.Sep.2012 7:53:23 AM   


Posts: 3542
Joined: 4.Apr.2005
From: Toronto, Canada
Status: offline
This seems like a DNS or network issue. Can you confirm all your servers especially the domain controllers have the correct DNS server entries. Obviously they must all be pointing to an internal DNS server! Also confirm that all exchange servers and domain controllers have a single NIC. If any of the servers has multiple NICs, please elaborate as to why they do and if any of these cards are active but not configured, make sure they are disabled!


Ibrahim Benna - Microsoft Exchange MVP
Forum Moderator

(in reply to swhite78)
Post #: 2
RE: Exchange 2010 AD Topology Discovery Failed - 17.Sep.2012 8:08:53 AM   


Posts: 2
Joined: 17.Sep.2012
Status: offline
All the servers are virtual servers with one virtual NIC. The 2 DCs are also DNS servers and they are used for the primary and secondary DNS server entries on the Exchange server NIC.

The 2 DCs are configured to use each other as the primary DNS server entry, with the loopback address as the secondary. External name resolution is handled by DNS server forwarders.

< Message edited by swhite78 -- 15.Oct.2012 6:45:12 AM >

(in reply to de.blackman)
Post #: 3

Page:   [1] << Older Topic    Newer Topic >>
All Forums >> [Microsoft Exchange 2010] >> General >> Exchange 2010 AD Topology Discovery Failed Page: [1]
Jump to:

New Messages No New Messages
Hot Topic w/ New Messages Hot Topic w/o New Messages
Locked w/ New Messages Locked w/o New Messages
 Post New Thread
 Reply to Message
 Post New Poll
 Submit Vote
 Delete My Own Post
 Delete My Own Thread
 Rate Posts

Follow TechGenix on Twitter