Issue Adding Internal Interface to Plesk Host causes Routing Issue

[Illiminator31]

Hello Plesk Community,
I have an Issue with my Plesk Installation, which is quite strange to me at the Moment.
My Plesk Installation is running in a Proxmox VM on Debian 10, but with its own Dedicated Public IPv4 Address routed via a PointoPoint Connection to the Gateway Router in the Datacenter, since the Router is in another IP Range. I wanted to centralize my Log Management and add my Internal Network to the Plesk Server, so I can collect the System logs via my Graylog Instance internally.

I added the Network Card as vmbr2 to my VM and configured it in the /etc/networking/interfaces to use my Sophos UTM as the Router for that Interface. So the Config would be: ens18 is my Public Facing Interface for the Internet and ens19 is my Internal only Interface.
However, after Restarting my Server, so the network Changes could take effect, Plesk was defaulting to my Internal IP Address with the Plesk Web panel etc and my Domains where not reachable. In the Hosting Settings the Public IP was still set and Mapping File i generated with "plesk bin reconfigurator /root/ip_map_file_name" did still show that my Public IP was set as the Interface IP. IP Manage via CLI showed both IP Addresses and neither a reread nor a removal of the Internal IP and reload did fix the Issue, so i had to issue a Rollback Backup.
Where was my Error? I never intended for the Internal IP to be available in Plesk for Management or Hosting Purposes, it should only serve for my Graylog Agent to be able to send logs to my internal Graylog, so i don't have to route everything via the Internet.

Cheers
Illiminator31

 

[Tozz]

You need to copy/paste your interfaces file and give your actual IP addresses. This is too vague to give any proper answer.
My guess is that you have two default gateways now, and traffic is routed over the wrong one.

 

[Illiminator31]

You need to copy/paste your interfaces file and give your actual IP addresses. This is too vague to give any proper answer.
My guess is that you have two default gateways now, and traffic is routed over the wrong one.

Hi,
this is the Interface File with redacted IP Addresses for Security Purposes.

#Loopback Iface for Agent auto lo iface lo inet loopback #Primary Config auto ens18 iface ens18 inet static address xxx.xxx.xxx.xxx netmask 255.255.255.255 gateway xxx.xxx.xxx.xxx pointopoint xxx.xxx.xxx.xxx #Secondary Config allow-hotplug ens19 iface ens19 inet static address xxx.xxx.xxx.xxx netmask 255.255.255.0 gateway xxx.xxx.xxx.xxx dns-nameservers xxx.xxx.xxx.xxx

ens18 is bound to a Physical Network Card in the Server, ens19 is bound to a Linux Bridge from Proxmox with no Physical Network Card.

 

[Tozz]

Yes so my assumption was correct.. You have configured two gateways, one for each interface.
You need to decide which interface you want to route traffic outside of your subnet(s) to. it can't be two

You need to remove one of the two gateways (and remove it from your routing table as well, or reboot)

Since you've redacted the IPs I cant tell you which one it should probably be.

 

[mow]

well, technically you can, but then you'll have to fiddle with priorities so only one is used at a time.