VPN vs. regular connection. Tunneling some services but not all.

[oshunluvr]

I'm not knowledgeable with IPtables or networking really. I only know enough to get it up and running. I'm working on Ubuntu Server 18.04 running headless that I access via SSH.

On the server, I would like to use both a VPN connection and a normal non-VPN connection for different services. The reasons are my media server isn't accessible behind the VPN and the VPN connection is considerably slower than my normal connection. So I would like to use both the ethernet connection (eno1 on my system) and the openvpn (tun0) connection, restricting the tun0 connection to specific services.

Here's where I'm at:
eno1 is set to a static IP using netplan:

[FONT=monospace][COLOR=#000000]# This file describes the network interfaces available on your system[/COLOR]
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  ethernets:
    eno1:
      dhcp4: no
      dhcp6: no
      addresses: [192.168.1.250/23]
      gateway4: 192.168.1.1
      nameservers:
        addresses: [8.8.8.8,8.8.4.4][/FONT]

With the VPN off, the route looks like:

[FONT=monospace][COLOR=#000000]Kernel IP routing table[/COLOR]
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eno1
192.168.0.0     0.0.0.0         255.255.254.0   U     0      0        0 eno1[/FONT]

With openvpn up and connected through my VPN (PIA if it matters), the route looks like:

[FONT=monospace][COLOR=#000000]Kernel IP routing table[/COLOR]
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.59.10.5      128.0.0.0       UG    0      0        0 tun0
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eno1
10.59.10.1      10.59.10.5      255.255.255.255 UGH   0      0        0 tun0
10.59.10.5      0.0.0.0         255.255.255.255 UH    0      0        0 tun0
107.191.33.6    192.168.1.1     255.255.255.255 UGH   0      0        0 eno1
128.0.0.0       10.59.10.5      128.0.0.0       UG    0      0        0 tun0
192.168.0.0     0.0.0.0         255.255.254.0   U     0      0        0 eno1[/FONT]

and the connection works as expected - I can "see" the internet though tun0 and have a different IP than the one provided by my ISP. But this seems to disable my ability to use eno1, i.e. I can ping google from tun0 but not eno1.

So either my openvpn connection is configured incorrectly, or I need some sort of other netplan or iptable routing - or all of the above. Suggestions?

[oshunluvr]

It might be worth mentioning that I also have second ethernet port that is not yet being used (but could be). In my 14.04 server install I used both ports via aggregation (binding) but I don't yet know how to do this with netplan vs. the old network/interfaces method.

[GreyGeek]

Can you ping google using Google's IP address instead of their domain name? If so, your netplan isn't providing DNS.

[oshunluvr]

With the VPN off using eno1 - I can ping google.
With the VPN on using tun0 - I can ping google.

With the VPN on using eno1 - I cannot ping google.

[GreyGeek]

With the VPN off using eno1 - I can ping google.
With the VPN on using eno1 - I cannot ping google.

Doesn't that make the question "How can I add DNS to eno1 when my VPN is on?"

PS- I'm probably asking the obvious. I've never used a VPN so I wouldn't know the answer to that question and if I DDG'd it I'd know no more than what you'd know doing a DDG search.

[oshunluvr]

Well, I'm not sure.

I believe when the VPN is on, it's using eno1. Thus I can't access it directly. I need to either configure the second ethernet port and let it run free while eno1 is locked to the VPN (which I think would be the preferred option), or access eno1 through a iptable routing.

I don't know enough to ask the correct question.

I tried enabling my second ethernet port (no VPN on at the time), but it doesn't connect to the internet and caused a frequent "pause" in my SSH connection.

Physically, both NICs are connected to the same switch, which connects to the modem. I don't know if this is part of the problem or not.

[oshunluvr]

Interestingly, having the VPN on did not cause a change in the SSH connection that I was aware of.