diff --git a/ip/iptunnel.c b/ip/iptunnel.c
index 3b46a159..b377a5b4 100644
--- a/ip/iptunnel.c
+++ b/ip/iptunnel.c
@@ -175,7 +175,7 @@ static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
 				usage();
 			if (p->name[0])
 				duparg2("name", *argv);
-			strncpy(p->name, *argv, IFNAMSIZ);
+			strncpy(p->name, *argv, IFNAMSIZ - 1);
 			if (cmd == SIOCCHGTUNNEL && count == 0) {
 				struct ip_tunnel_parm old_p;
 				memset(&old_p, 0, sizeof(old_p));