diff --git a/src/sentinel.c b/src/sentinel.c
index eb729966a..594b7e498 100644
--- a/src/sentinel.c
+++ b/src/sentinel.c
@@ -1839,7 +1839,7 @@ void sentinelPingInstance(sentinelRedisInstance *ri) {
         /* PUBLISH hello messages only to masters. */
         char ip[REDIS_IP_STR_LEN];
         if (anetSockName(ri->cc->c.fd,ip,sizeof(ip),NULL) != -1) {
-            char myaddr[128];
+            char myaddr[REDIS_IP_STR_LEN+128];
 
             // FIXME: IPv6 will break this due to nested : characters -geoffgarside
             snprintf(myaddr,sizeof(myaddr),"%s:%d:%s:%d",