diff --git a/src/pkg/net/port.go b/src/pkg/net/port.go
index cd18d2b42a..7d25058b29 100644
--- a/src/pkg/net/port.go
+++ b/src/pkg/net/port.go
@@ -18,7 +18,9 @@ var onceReadServices sync.Once
 func readServices() {
 	services = make(map[string]map[string]int)
 	var file *file
-	file, servicesError = open("/etc/services")
+	if file, servicesError = open("/etc/services"); servicesError != nil {
+		return
+	}
 	for line, ok := file.readLine(); ok; line, ok = file.readLine() {
 		// "http 80/tcp www www-http # World Wide Web HTTP"
 		if i := byteIndex(line, '#'); i >= 0 {