diff --git a/C4/SIP/Sip/Configuration.pm b/C4/SIP/Sip/Configuration.pm
index 819ec1d486..5c74b124a7 100644
--- a/C4/SIP/Sip/Configuration.pm
+++ b/C4/SIP/Sip/Configuration.pm
@@ -39,8 +39,8 @@ sub new {
     my %listeners;
 
     # The key to the listeners hash is the 'port' component of the
-    # configuration, which is of the form '[host]:[port]/proto', and
-    # the 'proto' component could be upper-, lower-, or mixed-cased.
+    # configuration, which is of the form '[host]:[port]/proto[/IPv[46]]'
+    # The 'proto' component could be upper-, lower-, or mixed-cased.
     # Regularize it here to lower-case, and then do the same below in
     # find_server() when building the keys to search the hash.
 
@@ -76,6 +76,10 @@ sub find_service {
         siplog( "LOG_DEBUG",
             "Configuration::find_service: Trying $portstr" );
         last if ( exists( ( $self->{listeners} )->{$portstr} ) );
+        $portstr .= '/ipv4';    # lc, see ->new
+        last if ( exists( ( $self->{listeners} )->{$portstr} ) );
+        $portstr .= '/ipv6';    # lc, see ->new
+        last if ( exists( ( $self->{listeners} )->{$portstr} ) );
     }
     return $self->{listeners}->{$portstr};
 }
diff --git a/debian/templates/SIPconfig.xml b/debian/templates/SIPconfig.xml
index 53b0638802..e79a2950b6 100644
--- a/debian/templates/SIPconfig.xml
+++ b/debian/templates/SIPconfig.xml
@@ -20,13 +20,13 @@
       protocol="NCIP/1.0" />
 -->
     <service
-      port="127.0.0.1:8023/tcp"
+      port="127.0.0.1:8023/tcp/IPv4"
       transport="telnet"
       protocol="SIP/2.00"
       timeout="60" />
 
     <service
-      port="127.0.0.1:6001/tcp"
+      port="127.0.0.1:6001/tcp/IPv4"
       transport="RAW"
       protocol="SIP/2.00"
       client_timeout="600"
diff --git a/etc/SIPconfig.xml b/etc/SIPconfig.xml
index 33f1859c9f..1816b91a23 100644
--- a/etc/SIPconfig.xml
+++ b/etc/SIPconfig.xml
@@ -29,13 +29,13 @@
       protocol="NCIP/1.0" />
 -->
     <service
-      port="8023/tcp"
+      port="127.0.0.1:8023/tcp/IPv4"
       transport="telnet"
       protocol="SIP/2.00"
       timeout="60" />
 
     <service
-      port="127.0.0.1:6001/tcp"
+      port="127.0.0.1:6001/tcp/IPv4"
       transport="RAW"
       protocol="SIP/2.00"
       client_timeout="600"