ssh: connect to host 192.168.0.200 port 22: No route to host

The context is the following:

I have installed Ubuntu server in a device at my home and set up a ssh server in this device. I can connect to this Ubuntu server through ssh without problems if the client device (Laptop in my case) is in the same local network. As I would like to access the server remotely, I installed openvpn3, this connection works fine too. But when I try to ssh (connected to another network, let's call "network B", than the server is, but with VPN connection active), I get the message:

ssh: connect to host 192.168.0.200 port 22: No route to host

I guess the reason is that network B's gateway tries to route to the devices inside network B's LAN instead of the server LAN. But I need to access the server's LAN in order to connect through ssh to my server with the private static IP address I set up to it.

Server's public IP:

$ curl ifconfig.me 181.31.117.40 

Answering to @cocomac

Just to check the obvious... is it 192.168.0. 200 or 192.168.1.200? Typically 192.168.1.XYZ is the default –

Proof that 192.168.0.200 is the server's IP:

$ ip addr 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: enp37s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 2c:f0:5d:78:39:a8 brd ff:ff:ff:ff:ff:ff inet 192.168.0.200/24 brd 192.168.0.255 scope global dynamic enp37s0 valid_lft 2528sec preferred_lft 2528sec inet6 fe80::2ef0:5dff:fe78:39a8/64 scope link valid_lft forever preferred_lft forever 

SSH when my laptop is in the same LAN:

sebastian@sebastian-Vostro-3405:~$ ssh sebademasi10@192.168.0.200 Welcome to Ubuntu 20.04.4 LTS (GNU/Linux 5.4.0-100-generic x86_64) * Documentation: * Management: * Support: System information as of Mon 28 Feb 2022 12:54:15 AM UTC System load: 0.09 Usage of /: 13.5% of 97.93GB Memory usage: 45% Swap usage: 0% Processes: 311 Users logged in: 0 IPv4 address for br-5c5a41a7cc73: 172.19.0.1 IPv4 address for br-974f16cf42ed: 172.18.0.1 IPv4 address for docker0: 172.17.0.1 IPv4 address for enp37s0: 192.168.0.200 * Super-optimized for small spaces - read how we shrank the memory footprint of MicroK8s to make it the smallest full K8s around. 0 updates can be applied immediately. Last login: Mon Feb 28 00:48:56 2022 from 192.168.0.110 sebademasi10@home:~$ 

Now, changing to my neighbor's network, I connect thought VPN:

~$ openvpn3 session-start -c home Using pre-loaded configuration profile 'home' Session path: /net/openvpn/v3/sessions/ca62d16csfcfcs43f1sa320s14f8bd92193e Connected 

Check Public IP:

sebastian@sebastian-Vostro-3405:~$ curl ifconfig.me 181.31.117.40 

ip route:

$ ip route 0.0.0.0/1 via 192.168.255.5 dev tun0 default via 192.168.0.1 dev wlp3s0 proto dhcp metric 600 128.0.0.0/1 via 192.168.255.5 dev tun0 169.254.0.0/16 dev wlp3s0 scope link metric 1000 172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 172.18.0.0/16 dev br-aa3d18e9a788 proto kernel scope link src 172.18.0.1 linkdown 172.19.0.0/16 dev br-7c64d12635b8 proto kernel scope link src 172.19.0.1 linkdown 172.20.0.0/16 dev br-118925d85563 proto kernel scope link src 172.20.0.1 linkdown 181.31.117.40 via 192.168.0.1 dev wlp3s0 192.168.0.0/24 dev wlp3s0 proto kernel scope link src 192.168.0.110 metric 600 192.168.255.1 via 192.168.255.5 dev tun0 192.168.255.4/30 dev tun0 proto kernel scope link src 192.168.255.6 

NOTE:

• Ther VPN server runs inside a Docker container

I hope this is easy to understand, please feel free to ask for any other details you consider needed. Thank you in advance.

1 Answer

I have solved this by manually adding (after connect to VPN) the route as follows:

ip route add 192.168.0.200 via 192.168.255.5

Where:

• 192.168.0.200 is the server's private IP
• 192.168.255.5 is the IP of the gateway in the server network

I realized this by checking ip route:

$ ip route 0.0.0.0/1 via 192.168.255.5 dev tun0 default via 192.168.0.1 dev wlp3s0 proto dhcp metric 600 128.0.0.0/1 via 192.168.255.5 dev tun0 169.254.0.0/16 dev wlp3s0 scope link metric 1000 172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown 172.18.0.0/16 dev br-aa3d18e9a788 proto kernel scope link src 172.18.0.1 linkdown 172.19.0.0/16 dev br-7c64d12635b8 proto kernel scope link src 172.19.0.1 linkdown 172.20.0.0/16 dev br-118925d85563 proto kernel scope link src 172.20.0.1 linkdown 181.31.117.40 via 192.168.0.1 dev wlp3s0 192.168.0.0/24 dev wlp3s0 proto kernel scope link src 192.168.0.110 metric 600 192.168.0.200 via 192.168.255.5 dev tun0 192.168.255.1 via 192.168.255.5 dev tun0 192.168.255.4/30 dev tun0 proto kernel scope link src 192.168.255.6