From 5ee7253552c51293a148a3eb878c893b8945a26c Mon Sep 17 00:00:00 2001
From: Brett Holman <brett.holman@canonical.com>
Date: Thu, 19 Oct 2023 08:47:11 -0600
Subject: [PATCH] network_manager: Assign routes to ip section by ip version

Fixes GH-4518
---
 cloudinit/net/network_manager.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/cloudinit/net/network_manager.py b/cloudinit/net/network_manager.py
index 8374cfcc878..922c69f7b3d 100644
--- a/cloudinit/net/network_manager.py
+++ b/cloudinit/net/network_manager.py
@@ -141,9 +141,14 @@ def _add_route(self, family, route):
         Adds a ipv[46].route<n> property.
         """
 
+        # family of the gateway must match the family of the route
+        gateway_family = "ipv6" if is_ipv6_address(route.get("gateway")) else "ipv4"
+        if gateway_family != family:
+            return
         value = route["network"] + "/" + str(route["prefix"])
         if "gateway" in route:
             value = value + "," + route["gateway"]
+
         self._add_numbered(family, "route", value)
 
     def _add_nameserver(self, dns):