<!-- solrconfig.xml for master instance -->
<requestHandler name="/replication" class="solr.ReplicationHandler" >
   <lst name="master">
       <str name="replicateAfter">startup</str>
       <str name="replicateAfter">commit</str>
       <!--If configuration files need to be replicated give the names here, separated by comma -->
       <str name="confFiles">schema.xml,stopwords.txt,elevate.xml</str>
       <str name="maxNumberOfBackups">0</str>
   </lst>
 </requestHandler>
<!-- solrconfig.xml in slave instances -->
<requestHandler name="/replication" class="solr.ReplicationHandler" >
     <lst name="slave">
       <str name="enable">true</str>
       <str name="masterUrl">https://load-balanced-url/solr/itembuckets</str>
       <str name="pollInterval">00:01:00</str>
       <str name="compression">internal</str>
       <str name="httpConnTimeout">5000</str>
       <str name="httpReadTimeout">10000</str>
     </lst>
</requestHandler>

WARN  Unable to connect to Solr: [http://SOLR_URL_:8984/solr/], the [SolrNet.Exceptions.SolrConnectionException] was caught.
Exception: SolrNet.Exceptions.SolrConnectionException
Message: Unable to connect to the remote server
Source: SolrNet
   at SolrNet.Impl.SolrConnection.Get(String relativeUrl, IEnumerable`1 parameters)
   at SolrNet.Impl.SolrCoreAdmin.Status()
   at Sitecore.ContentSearch.SolrProvider.SolrStatus.OkSolrStatus()

Nested Exception

Exception: System.Net.WebException
Message: Unable to connect to the remote server
Source: System
   at System.Net.HttpWebRequest.GetResponse()
   at HttpWebAdapters.Adapters.HttpWebRequestAdapter.GetResponse()
   at SolrNet.Impl.SolrConnection.GetResponse(IHttpWebRequest request)
   at SolrNet.Impl.SolrConnection.Get(String relativeUrl, IEnumerable`1 parameters)

Nested Exception

Exception: System.Net.Sockets.SocketException
Message: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 136.252.132.83:8984
Source: System
   at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Exception& exception)