Adding the above issue on my blog to help me remember as I forgot the commandlet to check for replication network communication issues between members of a DAG (damn limited memory of mine) – may be valid for Exchange 2013 as well (have to double-check this on my lab when I’ll have time between kids, regular work, administrative work, etc, etc)

SYMPTOMS:

If we encounter the following behavior :

1- Issues trying to Update-DatabaseCopy (error message saying that "An error occurred while communicating with server '<Server_Issue>'. Error: Unable to read data from the transport connection: an existing connection was forcibly closed by the remote host.")

2- 2153 MSExchangeRepl errors in the Application Log and NO OTHER RELATED ERRORS

3- Get-MailboxDatabaseCopyStatus -ConnectionStatus gives the above error on the "IncomingLogCopyingNetwork" parameter.

An error occurred while communicating with server '<Server_Name>'. Error: Unable to read data from the transport connection: an existing connection was forcibly closed by the remote host.

CAUSE:

Some network error on the Replication network causing the network replication to have issues…

WORKAROUND:

3 facts to remind first:

  • DAGs have 2 defined networks: MAPI Network and Replication Network.
  • Replication traffic (Log replication, Heartbeat traffic) goes through the Replication Network
  • Exception: Database seeding or re-seeding always goes through the MAPI network.

ACTION: disable replication on "Replication Network" + enable replication on "MAPI Network". then RESTART the MSExchange Replication service.

To see if it worked:

Get-MailboxDatabaseCopyStatus -ConnectionStatus | FT Identity,IncomingLogCopyingNetwork

You should see something like "{Server_Name,MAPI-Network}" on the IncomingLogCopyingNetwork column, and no "Error: Unable to read data...." subsequent message.

Raw issue data:

IncomingLogCopyingNetwork

SERVER_NAME

Replication_Network_name

An error occurred while communicating with server 'SERVER_NAME'. Error: Unable to read data from the transport connection: an existing connection was forcibly closed by the remote host.

Sam.