diff --git a/plugins/redis/redis.go b/plugins/redis/redis.go
index 95d5dc75b..f15d9557b 100644
--- a/plugins/redis/redis.go
+++ b/plugins/redis/redis.go
@@ -114,7 +114,7 @@ const defaultPort = "6379"
 func (r *Redis) gatherServer(addr *url.URL, acc plugins.Accumulator) error {
 	_, _, err := net.SplitHostPort(addr.Host)
 	if err != nil {
-		addr.Host = addr.Host + ":" + defaultPort
+		addr.Host = net.JoinHostPort(addr.Host, defaultPort)
 	}
 
 	c, err := net.Dial("tcp", addr.Host)