diff --git a/app/src/main/cpp/baresip.c b/app/src/main/cpp/baresip.c
index 8957b5de..94b045ef 100644
--- a/app/src/main/cpp/baresip.c
+++ b/app/src/main/cpp/baresip.c
@@ -941,12 +941,21 @@ Java_com_tutpro_baresip_Api_account_1stun_1uri(JNIEnv *env, jobject thiz, jstrin
         const struct stun_uri *stun_uri = account_stun_uri(acc);
         if (stun_uri) {
             char uri_str[256];
-            if (stun_uri->port != 0)
-                sprintf(uri_str, "%s:%s:%d", stunuri_scheme_name(stun_uri->scheme),
-                        stun_uri->host, stun_uri->port);
-            else
-                sprintf(uri_str, "%s:%s", stunuri_scheme_name(stun_uri->scheme),
-                        stun_uri->host);
+            if (stun_uri->port != 0) {
+                if (stun_uri->proto == IPPROTO_TCP)
+                    sprintf(uri_str, "%s:%s:%d?transport=tcp",
+                            stunuri_scheme_name(stun_uri->scheme), stun_uri->host, stun_uri->port);
+                else
+                    sprintf(uri_str, "%s:%s:%d",
+                            stunuri_scheme_name(stun_uri->scheme), stun_uri->host, stun_uri->port);
+            } else {
+                if (stun_uri->proto == IPPROTO_TCP)
+                    sprintf(uri_str, "%s:%s?transport=tcp",
+                            stunuri_scheme_name(stun_uri->scheme), stun_uri->host);
+                else
+                    sprintf(uri_str, "%s:%s",
+                            stunuri_scheme_name(stun_uri->scheme), stun_uri->host);
+            }
             return (*env)->NewStringUTF(env, uri_str);
         }
     }
diff --git a/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt b/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt
index 5e684a54..1d253aa6 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt
@@ -481,7 +481,8 @@ class AccountActivity : AppCompatActivity() {
                     if (((mediaNat == "stun") || (mediaNat == "ice")) && (newStunServer == ""))
                         newStunServer = resources.getString(R.string.stun_server_default)
                     if (!Utils.checkStunUri(newStunServer) ||
-                            ((mediaNat == "turn") && !newStunServer.startsWith("turn:"))) {
+                            (mediaNat == "turn" &&
+                                    newStunServer.substringBefore(":") !in setOf("turn", "turns"))) {
                         Utils.alertView(this, getString(R.string.notice),
                                 String.format(getString(R.string.invalid_stun_server), newStunServer))
                         return false
diff --git a/app/src/main/kotlin/com/tutpro/baresip/Utils.kt b/app/src/main/kotlin/com/tutpro/baresip/Utils.kt
index 2690f677..3397a1ac 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/Utils.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/Utils.kt
@@ -142,10 +142,17 @@ object Utils {
                         params[0] in arrayOf("transport=udp", "transport=tcp", "transport=tls"))
     }
 
+    private fun checkTransport(transport: String, transports: Set<String>): Boolean {
+        return transport.split("=")[0] == "transport" &&
+                transport.split("=")[1].lowercase() in transports
+    }
+
     fun checkStunUri(uri: String): Boolean {
-        if (!uri.startsWith("stun:") && !uri.startsWith("turn:"))
+        if (uri.substringBefore(":").lowercase() !in setOf("stun", "stuns", "turn", "turns"))
             return false
-        return checkHostPort(uri.substringAfter(":"))
+        return checkHostPort(uri.substringAfter(":").substringBefore("?")) &&
+                (uri.indexOf("?") == -1 ||
+                checkTransport(uri.substringAfter("?"), setOf("udp", "tcp")))
     }
 
     fun isE164Number(no: String): Boolean {
@@ -213,12 +220,11 @@ object Utils {
     }
 
     private fun checkParam(param: String): Boolean {
+        /* Todo: do proper check */
         val nameValue = param.split("=")
         if (nameValue.size == 1)
-            /* Todo: do proper check */
             return true
         if (nameValue.size == 2) {
-            /* Todo: do proper check */
             if ((nameValue[0] == "transport") &&
                 setOf("udp", "tcp", "tls", "wss").contains(nameValue[1].lowercase()))
             return true
diff --git a/app/src/main/res/values-fi/strings.xml b/app/src/main/res/values-fi/strings.xml
index 84bd4fa3..85679a26 100644
--- a/app/src/main/res/values-fi/strings.xml
+++ b/app/src/main/res/values-fi/strings.xml
@@ -167,8 +167,8 @@
         for NAT, RFC 5389) ja ICE (Interactive Connectivity Establishment, RFC 5245).
     </string>
     <string name="stun_server">STUN/TURN-palvelin</string>
-    <string name="stun_server_help">STUN/TURN-palvelimen muotoa \'kaava:palvelin[:portti]\'
-        oleva URI, missä kaava on \'stun\' tai \'turn\'. Oletus STUN-palvelin
+    <string name="stun_server_help">STUN/TURN-palvelimen muotoa \'kaava:palvelin[:portti][?transport=udp|tcp]\'
+        oleva URI, missä kaava on \'stun\', \'stuns\', \'turn\' tai \'turns\'. Oletus STUN-palvelin
         STUN- ja ICE-protokollille on \'stun:stun.l.google.com:19302\', joka osoittaa Google:n
         julkiseen STUN-palvelimeen. TURN-palvelimella ei ole oletusarvoa.
     </string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 632f95a3..e3cb7366 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -151,10 +151,10 @@
         Establishment, RFC 5245).
     </string>
     <string name="stun_server">STUN/TURN Server</string>
-    <string name="stun_server_help">A STUN/TURN Server URI of form scheme:host[:port], where scheme
-        is \'stun\' or \'turn\'. Factory default STUN Server for STUN and
-        ICE protocols is \'stun:stun.l.google.com:19302\' pointing to public Google STUN server.
-        There is no factory default TURN server.
+    <string name="stun_server_help">A STUN/TURN Server URI of form scheme:host[:port][?transport=udp|tcp],
+        where scheme is \'stun\', \'stuns\', \'turn\', or \'turns\'. Factory default STUN Server
+        for STUN and ICE protocols is \'stun:stun.l.google.com:19302\' pointing to public Google
+        STUN server. There is no factory default TURN server.
     </string>
     <string name="stun_server_uri">STUN/TURN Server URI</string>
     <string name="invalid_stun_server">Invalid STUN/TURN Server URI \'%1$s\'</string>