1 files changed, 14 insertions, 8 deletions
diff --git a/ssh/knownhosts/knownhosts.go b/ssh/knownhosts/knownhosts.go
index c022e41..1ebd7e6 100644
--- a/ssh/knownhosts/knownhosts.go
+++ b/ssh/knownhosts/knownhosts.go
@@ -421,20 +421,26 @@ func New(files ...string) (ssh.HostKeyCallback, error) {
 	return certChecker.CheckHostKey, nil
 }
 
-// Normalize normalizes an address into the form used in known_hosts
+// Normalize normalizes an address into the form used in known_hosts. Supports
+// IPv4, hostnames, bracketed IPv6. Any other non-standard formats are returned
+// with minimal transformation.
 func Normalize(address string) string {
+	const defaultSSHPort = "22"
+
 	host, port, err := net.SplitHostPort(address)
 	if err != nil {
 		host = address
-		port = "22"
+		port = defaultSSHPort
+	}
+
+	if strings.HasPrefix(host, "[") && strings.HasSuffix(host, "]") {
+		host = host[1 : len(host)-1]
 	}
-	entry := host
-	if port != "22" {
-		entry = "[" + entry + "]:" + port
-	} else if strings.Contains(host, ":") && !strings.HasPrefix(host, "[") {
-		entry = "[" + entry + "]"
+
+	if port == defaultSSHPort {
+		return host
 	}
-	return entry
+	return "[" + host + "]:" + port
 }
 
 // Line returns a line to add append to the known_hosts files.