From 7005e289dabb387bd835fdf7d9cdfc0e94e56359 Mon Sep 17 00:00:00 2001
From: "William A. Kennington III" <william@wkennington.com>
Date: Mon, 24 Nov 2014 18:01:02 -0800
Subject: [PATCH] nixos/network-interfaces: Promote secondary addresses when
 primary addresses expire

---
 nixos/modules/tasks/network-interfaces.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/nixos/modules/tasks/network-interfaces.nix b/nixos/modules/tasks/network-interfaces.nix
index 6fb6b77adb91..ca6240ac0949 100644
--- a/nixos/modules/tasks/network-interfaces.nix
+++ b/nixos/modules/tasks/network-interfaces.nix
@@ -576,6 +576,7 @@ in
       optionalString hasBonds "options bonding max_bonds=0";
 
     boot.kernel.sysctl = {
+      "net.net.ipv4.conf.all.promote_secondaries" = true;
       "net.ipv6.conf.all.disable_ipv6" = mkDefault (!cfg.enableIPv6);
       "net.ipv6.conf.default.disable_ipv6" = mkDefault (!cfg.enableIPv6);
       "net.ipv4.conf.all_forwarding" = mkDefault (any (i: i.proxyARP) interfaces);