My service works great under low load. But under high load I start to get connection errors. I know about other settings but I am trying to change the listenBacklog parameter in particular for my TCP Buffered binding. If I set listenBacklog="10" I am able to telnet into the port where my WCF service is running. If I change listenBacklog to anything higher than 10 it will not let me telnet into my service when it is running. No errors seem to be thrown. What can I do? I get the same problem when I change my maxConnections away from 10. All other properties of the binding I can set higher without a problem. Here is what my binding looks like: <bindings> <netTcpBinding> <binding name="NetTcpBinding_IMyService" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" transactionFlow="false" transferMode="Buffered" transactionProtocol="OleTransactions" hostNameComparisonMode="StrongWildcard" listenBacklog="10" maxBufferPoolSize="524288" maxBufferSize="1048576" maxConnections="10" maxReceivedMessageSize="1048576"> <readerQuotas maxDepth="2147483647" maxStringContentLength="2147483647" maxArrayLength="2147483647" maxBytesPerRead="2147483647" maxNameTableCharCount="2147483647" /> <reliableSession ordered="true" inactivityTimeout="00:10:00" enabled="false" /> <security mode="Transport"> <transport clientCredentialType="Windows" protectionLevel="EncryptAndSign"> </transport> <message clientCredentialType="Windows" /> </security> </binding> ... I really need to increase the values of maxConnections and listenBacklog