diff --git a/plugins/meta/portmap/portmap.go b/plugins/meta/portmap/portmap.go
index d35136f0..480431be 100644
--- a/plugins/meta/portmap/portmap.go
+++ b/plugins/meta/portmap/portmap.go
@@ -337,7 +337,7 @@ func genMarkMasqChain(markBit int) chain {
 // enableLocalnetRouting tells the kernel not to treat 127/8 as a martian,
 // so that connections with a source ip of 127/8 can cross a routing boundary.
 func enableLocalnetRouting(ifName string) error {
-	routeLocalnetPath := "net.ipv4.conf." + ifName + ".route_localnet"
+	routeLocalnetPath := "net/ipv4/conf/" + ifName + "/route_localnet"
 	_, err := sysctl.Sysctl(routeLocalnetPath, "1")
 	return err
 }