Look at this line:
https://github.com/jboss-remoting/jboss-remoting/blob/4.0.14.Final/src/main/java/org/jboss/remoting3/remote/ServerConnectionOpenListener.java#L100

This means that is no serverName is configured, creating a new Remoting connection always involves using a DNS server (InetServerAddress.getHostName()). This comes with a visible performance penalty - the handshake takes up to 200 milliseconds more than it needs to. Furthermore, we are observing an obscure bug which causes InetServerAddress.getHostName() sometimes take much more time than usual - around 5 seconds, which is enough to cause a connection timeout in some cases, eg. in the default settings of WildFly test suite, making some tests intermittently fail.

In case that no serverName is configured, the host name should be obtained only once and then re-used.

This performance penalty doesn't apply if the server is bound to a loopback address or to an address mapped within /etc/hosts - in that case, DNS is not involved and the initialization is fast.