diff -Nur asterisk-cvs/channels/chan_sip.c asterisk/channels/chan_sip.c
--- asterisk-cvs/channels/chan_sip.c    2005-01-09 01:37:55.000000000 +0100
+++ asterisk/channels/chan_sip.c        2005-01-09 01:36:37.000000000 +0100
@@ -648,18 +648,18 @@
         */
        struct sockaddr_in theirs;
        theirs.sin_addr = *them;
-       if (externexpire && (time(NULL) >= externexpire)) {
-               struct ast_hostent ahp;
-               struct hostent *hp;
-               time(&externexpire);
-               externexpire += externrefresh;
-               if ((hp = ast_gethostbyname(externhost, &ahp))) {
-                       memcpy(&externip.sin_addr, hp->h_addr, sizeof(externip));
-               } else
-                       ast_log(LOG_NOTICE, "Warning: Re-lookup of '%s' failed!\n", externhost);
-       }
        if (localaddr && externip.sin_addr.s_addr &&
           ast_apply_ha(localaddr, &theirs)) {
+               if (externexpire && (time(NULL) >= externexpire)) {
+                       struct ast_hostent ahp;
+                       struct hostent *hp;
+                       time(&externexpire);
+                       externexpire += externrefresh;
+                       if ((hp = ast_gethostbyname(externhost, &ahp))) {
+                               memcpy(&externip.sin_addr, hp->h_addr, sizeof(externip.sin_addr));
+                       } else
+                               ast_log(LOG_NOTICE, "Warning: Re-lookup of '%s' failed!\n", externhost);
+               }
                char iabuf[INET_ADDRSTRLEN];
                memcpy(us, &externip.sin_addr, sizeof(struct in_addr));
                ast_inet_ntoa(iabuf, sizeof(iabuf), *(struct in_addr *)&them->s_addr);