--- channels/chan_sip.c	2007-03-17 14:38:34.000000000 +0100
+++ channels/chan_sip.c	2007-03-17 16:40:02.000000000 +0100
@@ -148,6 +148,7 @@ static const char notify_config[] = "sip
 
 #define RTP 	1
 #define NO_RTP	0
+#define DEFAULT_USEEXTERNRTPIP   "yes"
 
 /* Do _NOT_ make any changes to this enum, or the array following it;
    if you think you are doing the right thing, you are probably
@@ -328,6 +329,7 @@ static const struct cfsip_options {
 #define DEFAULT_SIP_PORT	5060	/*!< From RFC 3261 (former 2543) */
 #define SIP_MAX_PACKET		4096	/*!< Also from RFC 3261 (2543), should sub headers tho */
 
+static char default_useexternrtpip[AST_MAX_EXTENSION];
 static char default_useragent[AST_MAX_EXTENSION] = DEFAULT_USERAGENT;
 
 #define DEFAULT_CONTEXT "default"
@@ -4589,6 +4591,9 @@ static int add_sdp(struct sip_request *r
 	/* We break with the "recommendation" and send our IP, in order that our
 	   peer doesn't have to ast_gethostbyname() us */
 
+	if (strcasestr(default_useexternrtpip, "no"))
+	  ast_ouraddrfor(&p->sa.sin_addr, &dest.sin_addr);
+
 	snprintf(v, sizeof(v), "v=0\r\n");
 	snprintf(o, sizeof(o), "o=root %d %d IN IP4 %s\r\n", p->sessionid, p->sessionversion, ast_inet_ntoa(iabuf, sizeof(iabuf), dest.sin_addr));
 	snprintf(s, sizeof(s), "s=session\r\n");
@@ -12681,6 +12686,7 @@ static int reload_config(void)
 	externrefresh = 10;
 	ast_copy_string(default_useragent, DEFAULT_USERAGENT, sizeof(default_useragent));
 	ast_copy_string(default_notifymime, DEFAULT_NOTIFYMIME, sizeof(default_notifymime));
+	ast_copy_string(default_useexternrtpip, DEFAULT_USEEXTERNRTPIP, sizeof(default_useexternrtpip));
 	global_notifyringing = 1;
 	global_alwaysauthreject = 0;
 	ast_copy_string(global_realm, DEFAULT_REALM, sizeof(global_realm));
@@ -12778,6 +12784,8 @@ static int reload_config(void)
 			videosupport = ast_true(v->value);
 		} else if (!strcasecmp(v->name, "compactheaders")) {
 			compactheaders = ast_true(v->value);
+		} else if (!strcasecmp(v->name, "useexternrtpip")) {
+		              ast_copy_string(default_useexternrtpip, v->value, sizeof(default_useexternrtpip));
 		} else if (!strcasecmp(v->name, "notifymimetype")) {
 			ast_copy_string(default_notifymime, v->value, sizeof(default_notifymime));
 		} else if (!strcasecmp(v->name, "notifyringing")) {