diff --git a/src/etc/inc/interfaces.inc b/src/etc/inc/interfaces.inc
index 91c3271ea..e8dfb5358 100644
--- a/src/etc/inc/interfaces.inc
+++ b/src/etc/inc/interfaces.inc
@@ -2620,17 +2620,17 @@ function interface_track6_6rd_configure($interface = 'lan', $lancfg)
     $rd6lanbin = str_pad($rd6lanbin, 128, "0", STR_PAD_RIGHT);
 
     /* convert the 128 bits for the lan address back into a valid IPv6 address */
-    $rd6lan = convert_128bit_to_ipv6($rd6lanbin) ."1";
+    $rd6lan = convert_128bit_to_ipv6($rd6lanbin) . (1 + get_interface_number_track6($lancfg['track6-interface'], $interface));
 
     $lanif = get_real_interface($interface, 'inet6');
     $oip = find_interface_ipv6($lanif);
     if (is_ipaddrv6($oip)) {
         mwexec("/sbin/ifconfig {$lanif} inet6 {$oip} delete");
     }
-    log_error("rd6 {$interface} with ipv6 address {$rd6lan} based on {$lancfg['track6-interface']} ipv4 {$ip4address}");
-    mwexec("/sbin/ifconfig {$lanif} inet6 {$rd6lan} prefixlen 64");
 
-    return 0;
+    log_error("rd6 {$interface} with ipv6 address {$rd6lan} based on {$lancfg['track6-interface']} ipv4 {$ip4address}");
+    /* XXX why 64? */
+    mwexec("/sbin/ifconfig {$lanif} inet6 {$rd6lan} prefixlen 64");
 }
 
 function interface_track6_6to4_configure($interface = 'lan', $lancfg)
@@ -2660,17 +2660,17 @@ function interface_track6_6to4_configure($interface = 'lan', $lancfg)
     $sixto4lanbin = str_pad($sixto4lanbin, 128, "0", STR_PAD_RIGHT);
 
     /* convert the 128 bits for the lan address back into a valid IPv6 address */
-    $sixto4lan = convert_128bit_to_ipv6($sixto4lanbin) ."1";
+    $sixto4lan = convert_128bit_to_ipv6($sixto4lanbin) . (1 + get_interface_number_track6($lancfg['track6-interface'], $interface));
 
     $lanif = get_real_interface($interface, 'inet6');
     $oip = find_interface_ipv6($lanif);
     if (is_ipaddrv6($oip)) {
         mwexec("/sbin/ifconfig {$lanif} inet6 {$oip} delete");
     }
-    log_error("sixto4 {$interface} with ipv6 address {$sixto4lan} based on {$lancfg['track6-interface']} ipv4 {$ip4address}");
-    mwexec("/sbin/ifconfig {$lanif} inet6 {$sixto4lan} prefixlen 64");
 
-    return 0;
+    log_error("sixto4 {$interface} with ipv6 address {$sixto4lan} based on {$lancfg['track6-interface']} ipv4 {$ip4address}");
+    /* XXX why 64? */
+    mwexec("/sbin/ifconfig {$lanif} inet6 {$sixto4lan} prefixlen 64");
 }
 
 function interface_6rd_configure($interface = 'wan', $wancfg)
@@ -2845,8 +2845,6 @@ function interface_6to4_configure($interface = 'wan', $wancfg)
     if (!file_exists("/var/run/booting")) {
         link_interface_to_track6($interface, true);
     }
-
-    return 0;
 }
 
 function interface_dhcpv6_configure($interface = 'wan', $wancfg)
@@ -3759,6 +3757,22 @@ function guess_interface_from_ip($ipaddress)
     return $ret;
 }
 
+function get_interface_number_track6($wanif, $targetif)
+{
+    $list = link_interface_to_track6($wanif);
+    $number = 0;
+
+    foreach ($list as $lanif => $unused) {
+        if ($lanif == $targetif) {
+            return $number;
+        }
+        $number += 1;
+    }
+
+    /* if we fail give backwards-compat */
+    return 0;
+}
+
 function link_interface_to_track6($wanif, $update = false)
 {
     $list = array();