--- chan_sip.c	2004-12-24 00:18:36.000000000 -0500
+++ /usr/src/asterisk-1.0.3/asterisk/channels/chan_sip.c	2004-12-23 21:23:53.000000000 -0500
@@ -555,6 +555,7 @@
 
 static struct sockaddr_in bindaddr;
 static struct sockaddr_in externip;
+static struct sockaddr_in internip;
 static struct ast_ha *localaddr;
 
 static struct ast_frame  *sip_read(struct ast_channel *ast);
@@ -634,6 +635,8 @@
 		ast_inet_ntoa(iabuf, sizeof(iabuf), *(struct in_addr *)&them->s_addr);
 		ast_log(LOG_DEBUG, "Target address %s is not local, substituting externip\n", iabuf);
 	}
+  else if (internip.sin_addr.s_addr)
+    memcpy(us, &internip.sin_addr, sizeof(struct in_addr));
 	else if (bindaddr.sin_addr.s_addr)
 		memcpy(us, &bindaddr.sin_addr, sizeof(struct in_addr));
 	else
@@ -8691,6 +8694,11 @@
 				localaddr = na;
 		} else if (!strcasecmp(v->name, "localmask")) {
 			ast_log(LOG_WARNING, "Use of localmask is no long supported -- use localnet with mask syntax\n");
+		} else if (!strcasecmp(v->name, "internip")) {
+			if (!(hp = ast_gethostbyname(v->value, &ahp))) 
+				ast_log(LOG_WARNING, "Invalid address for internip keyword: %s\n", v->value);
+			else
+				memcpy(&internip.sin_addr, hp->h_addr, sizeof(internip.sin_addr));
 		} else if (!strcasecmp(v->name, "externip")) {
 			if (!(hp = ast_gethostbyname(v->value, &ahp))) 
 				ast_log(LOG_WARNING, "Invalid address for externip keyword: %s\n", v->value);