Use net.JoinHostPort for adding the port to the host (thx Sam)

connect.go

@@ -69,7 +69,7 @@ func connect(options xmpp.Options, directTLS bool) (*xmpp.Client, error) {
 					// Use StartTLS
 					options.NoTLS = true
 					options.StartTLS = true
-					options.Host = fmt.Sprintf("%s:%d", adr.host, adr.port)
+					options.Host = net.JoinHostPort(adr.host, fmt.Sprint(adr.port))
 					// Connect to server
 					client, err := options.NewClient()
 					if err == nil {
@@ -79,7 +79,7 @@ func connect(options xmpp.Options, directTLS bool) (*xmpp.Client, error) {
 					// Use direct TLS
 					options.NoTLS = false
 					options.StartTLS = false
-					options.Host = fmt.Sprintf("%s:%d", adr.host, adr.port)
+					options.Host = net.JoinHostPort(adr.host, fmt.Sprint(adr.port))
 					// Connect to server
 					client, err := options.NewClient()
 					if err == nil {
@@ -92,7 +92,7 @@ func connect(options xmpp.Options, directTLS bool) (*xmpp.Client, error) {
 		// Try port 5222 if no xmpp-client SRV records are provided.
 		options.NoTLS = true
 		options.StartTLS = true
-		options.Host = fmt.Sprintf("%s:%d", server, 5222)
+		options.Host = net.JoinHostPort(server, "5222")
 		// Connect to server
 		client, err := options.NewClient()
 		return client, err