diff --git a/ChangeLog b/ChangeLog
index 52d5064..ddb000e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,8 @@
 0.5.12
 ======
    9-Oct-2005:  - Expiration timeout is now taken from the REGISTER response
+                - fix: no audio with some UAs that do not include a
+                  Contact header in ACK messages (which is compliant).
    1-Oct-2005:  - [1278537] Read proxy_auth_pwfile after config file is read
                 - [1278591] Proxy-Authenticate header not included in response
                 - process empty Contact header (means "query registrations")
diff --git a/src/proxy.c b/src/proxy.c
index 0e6844b..db45f50 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -271,11 +271,11 @@ int proxy_request (sip_ticket_t *ticket) {
       /* check for incoming request */
       } else if (MSG_IS_INVITE(request)) {
          /* Rewrite the body */
-         sts = proxy_rewrite_invitation_body(request, DIR_INCOMING);
+         sts = proxy_rewrite_invitation_body(ticket, DIR_INCOMING);
 
       } else if (MSG_IS_ACK(request)) {
          /* Rewrite the body */
-         sts = proxy_rewrite_invitation_body(request, DIR_INCOMING);
+         sts = proxy_rewrite_invitation_body(ticket, DIR_INCOMING);
 
       }
       break;
@@ -320,9 +320,9 @@ int proxy_request (sip_ticket_t *ticket) {
 
       /* if an INVITE, rewrite body */
       if (MSG_IS_INVITE(request)) {
-         sts = proxy_rewrite_invitation_body(request, DIR_OUTGOING);
+         sts = proxy_rewrite_invitation_body(ticket, DIR_OUTGOING);
       } else if (MSG_IS_ACK(request)) {
-         sts = proxy_rewrite_invitation_body(request, DIR_OUTGOING);
+         sts = proxy_rewrite_invitation_body(ticket, DIR_OUTGOING);
       }
 
       /* if this is CANCEL/BYE request, stop RTP proxying */
@@ -767,7 +767,7 @@ int proxy_response (sip_ticket_t *ticket) {
          if ((MSG_IS_STATUS_1XX(response)) || 
               (MSG_IS_STATUS_2XX(response))) {
             if (configuration.rtp_proxy_enable == 1) {
-               sts = proxy_rewrite_invitation_body(response, DIR_INCOMING);
+               sts = proxy_rewrite_invitation_body(ticket, DIR_INCOMING);
             }
          /* negative - stop a possibly started RTP stream */
          } else if ((MSG_IS_STATUS_4XX(response))  ||
@@ -849,7 +849,7 @@ int proxy_response (sip_ticket_t *ticket) {
          if ((MSG_IS_STATUS_1XX(response)) || 
               (MSG_IS_STATUS_2XX(response))) {
             /* This is an outgoing response, therefore an outgoing stream */
-            sts = proxy_rewrite_invitation_body(response, DIR_OUTGOING);
+            sts = proxy_rewrite_invitation_body(ticket, DIR_OUTGOING);
          /* megative - stop a possibly started RTP stream */
          } else if ((MSG_IS_STATUS_4XX(response))  ||
                      (MSG_IS_STATUS_5XX(response)) ||
@@ -978,7 +978,8 @@ int proxy_response (sip_ticket_t *ticket) {
  *	STS_SUCCESS on success
  *	STS_FAILURE on error
  */
-int proxy_rewrite_invitation_body(osip_message_t *mymsg, int direction){
+int proxy_rewrite_invitation_body(sip_ticket_t *ticket, int direction){
+   osip_message_t *mymsg=ticket->sipmsg;
    osip_body_t *body;
    sdp_message_t  *sdp;
    struct in_addr map_addr, addr_sess, addr_media, outside_addr, inside_addr;
@@ -1204,6 +1205,8 @@ if (configuration.debuglevel)
              * 1) User part of Contact header
              * 2) Host part of Contact header (will be different
              *    between internal UA and external UA)
+             * 3) IP address of sender (also different between
+             *    internal and external UA)
              */
             if (!osip_list_eol(mymsg->contacts, 0))
                cont_url = ((osip_contact_t*)(mymsg->contacts->node->element))->url;
@@ -1211,7 +1214,14 @@ if (configuration.debuglevel)
                client_id=cont_url->username;
                if (client_id == NULL) client_id=cont_url->host;
             }
-
+            if (client_id == NULL) {
+               static char from_string[HOSTNAME_SIZE];
+               char *tmp;
+               tmp=utils_inet_ntoa(ticket->from.sin_addr);
+               strncpy(from_string, tmp, HOSTNAME_SIZE-1);
+               from_string[HOSTNAME_SIZE-1]='\0';
+               client_id=tmp;
+            }
 
             /*
              * do we have a 'c=' item on media level?
diff --git a/src/rtpproxy_relay.c b/src/rtpproxy_relay.c
index 01b362e..fd11211 100644
--- a/src/rtpproxy_relay.c
+++ b/src/rtpproxy_relay.c
@@ -544,7 +544,6 @@ int rtp_relay_start_fwd (osip_call_id_t *callid, char *client_id,
         i2 < (num_ports + prev_used_port - configuration.rtp_port_low + 1);
         i2++) {
       i = (i2%num_ports) + configuration.rtp_port_low;
-DEBUGC(DBCLASS_RTP,"&&&& I=%i, i2=%i",i,i2);
 
       /* only allow even port numbers */
       if ((i % 2) != 0) continue;
diff --git a/src/siproxd.h b/src/siproxd.h
index 2f6b53b..2897e4e 100644
--- a/src/siproxd.h
+++ b/src/siproxd.h
@@ -136,7 +136,7 @@ int  register_set_expire(sip_ticket_t *ticket);				/*X*/
 /* proxy.c */
 int proxy_request (sip_ticket_t *ticket);				/*X*/
 int proxy_response (sip_ticket_t *ticket);				/*X*/
-int proxy_rewrite_invitation_body(osip_message_t *m, int direction);    /*X*/
+int proxy_rewrite_invitation_body(sip_ticket_t *ticket, int direction); /*X*/
 int proxy_rewrite_request_uri(osip_message_t *mymsg, int idx);		/*X*/
 
 /* route_preprocessing.c */