TCP Relay Binding (azure / service bus)

The azure service bus has 3 modes of operation, tcp, http and auto-detect (correction:- tcp is the default)... This initially confused me; we were testing a simple scenario hosting a service on-premise and invoking it from the cloud via the service bus and relay. We need tcp but were expecting the connection to be refused as the ports were not yet open.
Whilst our firewall logs showed the tcp connection was refused as expected - the connection was then established over http.
Because we need tcp in our scenario, we're going to need to configure the service bus system connectivity mode to tcp (and not the default auto detect).

You can do this in the global asax

ServiceBusEnvironment.SystemConnectivity.Mode = ConnectivityMode.Tcp;


(At time of writing this will avoid a ping to the MS watchdog address when the service starts)


If you're hosting in WCF and can't add global asax then add a custom service behaviour extension

If you have a requirement to authenticate client credentials check out

this post

Which explains how to configure the service to flow client credentials from caller to service where a custom password validator component (very easy to write) can be configured to provide the validation