diff --git a/lib/api/api.go b/lib/api/api.go
index f22b28bfb..b3ca1c590 100644
--- a/lib/api/api.go
+++ b/lib/api/api.go
@@ -1772,8 +1772,13 @@ func addressIsLocalhost(addr string) bool {
 		// There was no port, so we assume the address was just a hostname
 		host = addr
 	}
-	switch strings.ToLower(host) {
-	case "localhost", "localhost.":
+	host = strings.ToLower(host)
+	switch {
+	case host == "localhost":
+		return true
+	case host == "localhost.":
+		return true
+	case strings.HasSuffix(host, ".localhost"):
 		return true
 	default:
 		ip := net.ParseIP(host)
diff --git a/lib/api/api_test.go b/lib/api/api_test.go
index 7bd18db54..0b60e4902 100644
--- a/lib/api/api_test.go
+++ b/lib/api/api_test.go
@@ -995,14 +995,14 @@ func TestAddressIsLocalhost(t *testing.T) {
 		{"[::1]:8080", true},
 		{"127.0.0.1:8080", true},
 		{"127.23.45.56:8080", true},
+		{"www.localhost", true},
+		{"www.localhost:8080", true},
 
 		// These are all non-localhost addresses
 		{"example.com", false},
 		{"example.com:8080", false},
 		{"localhost.com", false},
 		{"localhost.com:8080", false},
-		{"www.localhost", false},
-		{"www.localhost:8080", false},
 		{"192.0.2.10", false},
 		{"192.0.2.10:8080", false},
 		{"0.0.0.0", false},