none
2012 Server Setting up Replication between Sites failing

    Question

  • Hi,

    Ive put up two 2012 servers which I are meant to be in separate SITES. The fist installed ok then the second was added and put on a separate site/subnet/link. Both DCs - essentially equal in roles.

    2nd server can been seen in SERVER MANAGER after adding it on the first server and vice versa - and I can see all the nice erros telling me there is no replication!

    I ploughed though hundreds of errors - most seem high level caused by an underlying failure somewhere. I couldnt solve so put both into the same SITE/SUBNET and replication finally ran ok.

    Now the first server is running with users connected I need to remove the 2nd server to its own site. I tried again and get no replication - again I can ping the FQDN of each on both servers, copy files, remote manage etc.

    repadmin /replsummary gives:

    Source DSA          largest delta    fails/total %%   error
     SERVER1                04h:45m:11s    5 /   5  100  (1722) The RPC server is unavailable.
     SERVER2                  05h:50m:43s    5 /   5  100  (8524) The DSA operation is unable to proceed because of a
     DNS lookup failure.


    Destination DSA     largest delta    fails/total %%   error
     SERVER1                05h:50m:43s    5 /   5  100  (8524) The DSA operation is unable to proceed because of a
     DNS lookup failure.
     SERVER2                  04h:45m:11s    5 /   5  100  (1722) The RPC server is unavailable.

    ..yet I can ping, and as they are different subnets across a router it definitely is using DNS.

    Any thoughts?.. (there are hundreds of other errors that this causes so posting more seemed a bit pointless..)

    (note.. the best fix wins a prize..)

    Wednesday, July 17, 2013 5:05 AM

Answers

  • Thanks, as per my post DNS was working ok.

    I solved this by creating a new 'Test' site, creating a new Subnet and Site Link (IP) and moving (drag) the 'remote' server to that - then replication finally kicked in.

    After re-checking all settings the original 'Transport:' drop down of one servers NTDS object (AD Sites and Services) was blank - it should have been set to IP by default and I think that had stopped initial replication to the first site.

    One thing to help trouble shooting I found is to reduce link replication interval from 3 hours down to 15 minutes (Inter-Site Transports\IP\DEFAULTSITELINK Properties).

    After making any site link changes manually request a 'Relplicate configuration to the selected DC' to push the site configuration info to the remote DC. (AD Sites and Services/Sites/<remote site>/Servers/<server_name>/ right click NTDS Settings - 'Replicate configuration to the selected DC').

    After this you can 'Replicate Now' by right clicking the NTDS Settings object in the right pane (the '<Automatically Generated> entry - unless it got renamed).

    The main issue was that having a link fail to connect generates hundreds of unhelpful 'critical DNS failure', 'RPC failure', 'AD replication failure' etc messages that simply point to each other and dont help solve the issue.

    I would say:

    1. Test DNS PING of the remote server (and back) and test other connectivity is ok (e.g. can you see the remote server in Server Manager, copy files, etc - if not then its a DNS/name resolution/basic connectivity related

    2. If the above works ok but replication doesnt then check the logical Site setup and how the sites talk to each other and their links. Create a test Site and Link. Use REPADMIN to check the status and remember that the default replcation period is 180 minutes by default.



    • Edited by SpeedStep Wednesday, July 24, 2013 2:20 AM added bit
    • Marked as answer by SpeedStep Wednesday, July 24, 2013 9:42 AM
    Wednesday, July 24, 2013 2:18 AM

All replies

  • Hi,

    Thanks for your posting.

    Please check this article,this topic explains symptoms, causes and how to resolve Active Directory replication error 8524 The DSA operation is unable to proceed because of a DNS lookup failure.

    http://technet.microsoft.com/en-us/library/replication-error-8524-the-dsa-operation-is-unable-to-proceed-because-of-a-dns-lookup-failure(WS.10).aspx

    Regards.


    Vivian Wang
    TechNet Community Support

    Monday, July 22, 2013 9:46 AM
    Moderator
  • Thanks, as per my post DNS was working ok.

    I solved this by creating a new 'Test' site, creating a new Subnet and Site Link (IP) and moving (drag) the 'remote' server to that - then replication finally kicked in.

    After re-checking all settings the original 'Transport:' drop down of one servers NTDS object (AD Sites and Services) was blank - it should have been set to IP by default and I think that had stopped initial replication to the first site.

    One thing to help trouble shooting I found is to reduce link replication interval from 3 hours down to 15 minutes (Inter-Site Transports\IP\DEFAULTSITELINK Properties).

    After making any site link changes manually request a 'Relplicate configuration to the selected DC' to push the site configuration info to the remote DC. (AD Sites and Services/Sites/<remote site>/Servers/<server_name>/ right click NTDS Settings - 'Replicate configuration to the selected DC').

    After this you can 'Replicate Now' by right clicking the NTDS Settings object in the right pane (the '<Automatically Generated> entry - unless it got renamed).

    The main issue was that having a link fail to connect generates hundreds of unhelpful 'critical DNS failure', 'RPC failure', 'AD replication failure' etc messages that simply point to each other and dont help solve the issue.

    I would say:

    1. Test DNS PING of the remote server (and back) and test other connectivity is ok (e.g. can you see the remote server in Server Manager, copy files, etc - if not then its a DNS/name resolution/basic connectivity related

    2. If the above works ok but replication doesnt then check the logical Site setup and how the sites talk to each other and their links. Create a test Site and Link. Use REPADMIN to check the status and remember that the default replcation period is 180 minutes by default.



    • Edited by SpeedStep Wednesday, July 24, 2013 2:20 AM added bit
    • Marked as answer by SpeedStep Wednesday, July 24, 2013 9:42 AM
    Wednesday, July 24, 2013 2:18 AM