diff --git a/src/libosmo-mgcp-client/mgcp_client.c b/src/libosmo-mgcp-client/mgcp_client.c
index d868c7f..593d305 100644
--- a/src/libosmo-mgcp-client/mgcp_client.c
+++ b/src/libosmo-mgcp-client/mgcp_client.c
@@ -363,6 +363,13 @@
 				rc = -EINVAL;
 				goto exit;
 			}
+
+			/* A specific endpoint identifier returned by the MGW
+			 * must contain an @ character */
+			if (strstr(r->head.endpoint, "@") == NULL) {
+				rc = -EINVAL;
+				goto exit;
+			}
 			break;
 		case 'I':
 			rc = mgcp_parse_head_param(r->head.conn_id,