Change default IPv6 multicast address (fixes #2090)

lib/config/config.go

@@ -218,7 +218,7 @@ type OptionsConfiguration struct {
 	GlobalAnnEnabled        bool     `xml:"globalAnnounceEnabled" json:"globalAnnounceEnabled" default:"true"`
 	LocalAnnEnabled         bool     `xml:"localAnnounceEnabled" json:"localAnnounceEnabled" default:"true"`
 	LocalAnnPort            int      `xml:"localAnnouncePort" json:"localAnnouncePort" default:"21025"`
-	LocalAnnMCAddr          string   `xml:"localAnnounceMCAddr" json:"localAnnounceMCAddr" default:"[ff32::5222]:21026"`
+	LocalAnnMCAddr          string   `xml:"localAnnounceMCAddr" json:"localAnnounceMCAddr" default:"[ff12::8384]:21027"`
 	RelayServers            []string `xml:"relayServer" json:"relayServers" default:"dynamic+https://relays.syncthing.net"`
 	MaxSendKbps             int      `xml:"maxSendKbps" json:"maxSendKbps"`
 	MaxRecvKbps             int      `xml:"maxRecvKbps" json:"maxRecvKbps"`
@@ -504,6 +504,11 @@ func convertV11V12(cfg *Configuration) {
 		}
 	}
 
+	// Use new multicast group
+	if cfg.Options.LocalAnnMCAddr == "[ff32::5222]:21026" {
+		cfg.Options.LocalAnnMCAddr = "[ff12::8384]:21027"
+	}
+
 	cfg.Version = 12
 }
 

lib/config/config_test.go

@@ -36,7 +36,7 @@ func TestDefaultValues(t *testing.T) {
 		GlobalAnnEnabled:        true,
 		LocalAnnEnabled:         true,
 		LocalAnnPort:            21025,
-		LocalAnnMCAddr:          "[ff32::5222]:21026",
+		LocalAnnMCAddr:          "[ff12::8384]:21027",
 		RelayServers:            []string{"dynamic+https://relays.syncthing.net"},
 		MaxSendKbps:             0,
 		MaxRecvKbps:             0,

test/h1/config.xml

@@ -51,7 +51,7 @@
         <globalAnnounceEnabled>false</globalAnnounceEnabled>
         <localAnnounceEnabled>true</localAnnounceEnabled>
         <localAnnouncePort>21025</localAnnouncePort>
-        <localAnnounceMCAddr>[ff32::5222]:21026</localAnnounceMCAddr>
+        <localAnnounceMCAddr>[ff12::8384]:21027</localAnnounceMCAddr>
         <relayServer>dynamic+https://relays.syncthing.net</relayServer>
         <maxSendKbps>0</maxSendKbps>
         <maxRecvKbps>0</maxRecvKbps>

test/h2/config.xml

@@ -55,7 +55,7 @@
         <globalAnnounceEnabled>false</globalAnnounceEnabled>
         <localAnnounceEnabled>true</localAnnounceEnabled>
         <localAnnouncePort>21025</localAnnouncePort>
-        <localAnnounceMCAddr>[ff32::5222]:21026</localAnnounceMCAddr>
+        <localAnnounceMCAddr>[ff12::8384]:21027</localAnnounceMCAddr>
         <relayServer>dynamic+https://relays.syncthing.net</relayServer>
         <maxSendKbps>0</maxSendKbps>
         <maxRecvKbps>0</maxRecvKbps>

test/h3/config.xml

@@ -44,7 +44,7 @@
         <globalAnnounceEnabled>false</globalAnnounceEnabled>
         <localAnnounceEnabled>false</localAnnounceEnabled>
         <localAnnouncePort>21025</localAnnouncePort>
-        <localAnnounceMCAddr>[ff32::5222]:21026</localAnnounceMCAddr>
+        <localAnnounceMCAddr>[ff12::8384]:21027</localAnnounceMCAddr>
         <relayServer>dynamic+https://relays.syncthing.net</relayServer>
         <maxSendKbps>0</maxSendKbps>
         <maxRecvKbps>0</maxRecvKbps>

test/h4/config.xml

@@ -23,7 +23,7 @@
         <globalAnnounceEnabled>false</globalAnnounceEnabled>
         <localAnnounceEnabled>false</localAnnounceEnabled>
         <localAnnouncePort>21025</localAnnouncePort>
-        <localAnnounceMCAddr>[ff32::5222]:21026</localAnnounceMCAddr>
+        <localAnnounceMCAddr>[ff12::8384]:21027</localAnnounceMCAddr>
         <relayServer>dynamic+https://relays.syncthing.net</relayServer>
         <maxSendKbps>0</maxSendKbps>
         <maxRecvKbps>0</maxRecvKbps>