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I am using Hetzner cloud where I created 2 servers in a subnet (10.1.0.0/24) - one only with local ip, another one has public IP and is used as a NAT gateway for the first server.

On private server I configured an ip route

ip route add default via 10.1.0.1 dev enp7s0 onlink

Here is a resulting list of routes

root:~# ip route show

default via 10.1.0.1 dev enp7s0 onlink 
10.1.0.0/16 via 10.1.0.1 dev enp7s0 
10.1.0.1 dev enp7s0 scope link 
169.254.169.254 via 10.1.0.1 dev enp7s0

DNS are configured in /etc/systemd/resolved.conf

[Resolve]
DNS=8.8.8.8 8.8.4.4

The problem is I can't persist default ip route so it is loaded after reboot. I tried using iptables-save but it doesn't output any routes, even those loaded at boot time (all except default).

I know that netplan is used and is configured somehow by Hetzner, as there is a stub file /etc/netplan/50-cloud-init.yaml though it doesn't has any network device config

Here is a list of network devices:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
 valid_lft forever preferred_lft forever
inet6 ::1/128 scope host 
valid_lft forever preferred_lft forever
2: enp7s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc fq_codel state UP group default qlen 1000
link/ether 86:00:00:2b:7f:7c brd ff:ff:ff:ff:ff:ff
inet 10.1.0.2/32 brd 10.1.0.2 scope global dynamic enp7s0
   valid_lft 84299sec preferred_lft 84299sec
inet6 fe80::8400:ff:fe2b:7f7c/64 scope link 
   valid_lft forever preferred_lft forever

Can I use it instead of default ip route to configure gateway? If yes, how?

Vladyslav Melnychenko
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  • `iptables-save` export IPTables rules into stdout. It does not save them in any file, and it does not help with routes. `ip route` is only a tool for runtime configuration. Persistent set up of network configuration is done via any networking toolset that is used on the server: Netplan, ifupdown etc. You need to find out which toolset is used on your server and change its configuration. – Tero Kilkanen Nov 28 '22 at 22:06
  • @TeroKilkanen I was exporting with iptables-save to file, and the file was empty, default route wasn't there – Vladyslav Melnychenko Nov 28 '22 at 23:13
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    As I told above, `iptables-save` only saves firewall rules. Routes are not in firewall rules. – Tero Kilkanen Nov 29 '22 at 07:58

0 Answers0