Add dns fetching for external ip

cmd/serve.go

@@ -30,6 +30,12 @@ func serveCmd(version string) cli.Command {
 			if exit {
 				os.Exit(1)
 			}
+
+			if _, _, err := conf.TurnIPProvider.Get(); err != nil {
+				// error is already logged by .Get()
+				os.Exit(1)
+			}
+
 			users, err := auth.ReadPasswordsFile(conf.UsersFile, conf.Secret, conf.SessionTimeoutSeconds)
 			if err != nil {
 				log.Fatal().Str("file", conf.UsersFile).Err(err).Msg("While loading users file")