diff --git a/src/cluster.c b/src/cluster.c
index 5819d872b..4e42737fb 100644
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -1465,7 +1465,8 @@ int clusterProcessPacket(clusterLink *link) {
 
     /* Perform sanity checks */
     if (totlen < 16) return 1; /* At least signature, version, totlen, count. */
-    if (ntohs(hdr->ver) != 0) return 1; /* Can't handle versions other than 0.*/
+    if (ntohs(hdr->ver) != CLUSTER_PROTO_VER)
+        return 1; /* Can't handle versions other than the current one.*/
     if (totlen > sdslen(link->rcvbuf)) return 1;
     if (type == CLUSTERMSG_TYPE_PING || type == CLUSTERMSG_TYPE_PONG ||
         type == CLUSTERMSG_TYPE_MEET)
@@ -2029,6 +2030,7 @@ void clusterBuildMessageHdr(clusterMsg *hdr, int type) {
               myself->slaveof : myself;
 
     memset(hdr,0,sizeof(*hdr));
+    hdr->ver = htons(CLUSTER_PROTO_VER);
     hdr->sig[0] = 'R';
     hdr->sig[1] = 'C';
     hdr->sig[2] = 'm';
diff --git a/src/cluster.h b/src/cluster.h
index 7d6567d45..ef5caf0d6 100644
--- a/src/cluster.h
+++ b/src/cluster.h
@@ -163,10 +163,11 @@ typedef struct {
     char nodename[REDIS_CLUSTER_NAMELEN];
     uint32_t ping_sent;
     uint32_t pong_received;
-    char ip[REDIS_IP_STR_LEN];    /* IP address last time it was seen */
-    uint16_t port;  /* port last time it was seen */
-    uint16_t flags;
-    uint32_t notused; /* for 64 bit alignment */
+    char ip[REDIS_IP_STR_LEN];  /* IP address last time it was seen */
+    uint16_t port;              /* port last time it was seen */
+    uint16_t flags;             /* node->flags copy */
+    uint16_t notused1;          /* Some room for future improvements. */
+    uint32_t notused2;
 } clusterMsgDataGossip;
 
 typedef struct {
@@ -211,6 +212,7 @@ union clusterMsgData {
     } update;
 };
 
+#define CLUSTER_PROTO_VER 0 /* Cluster bus protocol version. */
 
 typedef struct {
     char sig[4];        /* Siganture "RCmb" (Redis Cluster message bus). */
diff --git a/src/redis.h b/src/redis.h
index 89d97f55e..0c191d06f 100644
--- a/src/redis.h
+++ b/src/redis.h
@@ -131,7 +131,7 @@ typedef long long mstime_t; /* millisecond time type. */
 #define REDIS_DEFAULT_AOF_REWRITE_INCREMENTAL_FSYNC 1
 #define REDIS_DEFAULT_MIN_SLAVES_TO_WRITE 0
 #define REDIS_DEFAULT_MIN_SLAVES_MAX_LAG 10
-#define REDIS_IP_STR_LEN INET6_ADDRSTRLEN
+#define REDIS_IP_STR_LEN 46 /* INET6_ADDRSTRLEN is 46, but we need to be sure */
 #define REDIS_PEER_ID_LEN (REDIS_IP_STR_LEN+32) /* Must be enough for ip:port */
 #define REDIS_BINDADDR_MAX 16
 #define REDIS_MIN_RESERVED_FDS 32