External IP - strange behavior

[suther]

SYSTEM INFORMATION
OS type and version	Ubuntu Linux 20.04.5
Webmin version	2.010
Usermin version	1.860
Virtualmin version	7.5
Theme version	20.10
Package updates	All installed packages are up to date

I do have a server at Hetzner-Cloud where I’ve playing a bit around to test some stuff.
The Server does have the IP: 49.12.235.22 AND a Failover-IP/Floating-IP: 78.47.141.18

I’ve configured virtualmin like that:

Virtualmin > Addresses & Networking > Shared IP:

But it put me all the time the IP of “49…12.235.22” into DNS-Settings.

I’ve found a setting in Virtualmin-Config to force another IP:

But this produce following Notice / Warning if I do check the config:

Question: Is there better way to pre-configure that the right IP (Floating-IP) is used in DNS-Settings if I create a new VirtualServer, or can I ignore the warning and go with it like I’ve set it up now?

[jimr1]

Are you using Ubuntu 22.04 ?

[suther]

Ubuntu Linux 20.04.5

[jimr1]

Is the vps/server using netplan for network management

[suther]

yes

network:
  version: 2
  ethernets:
    eth0:
      addresses:
      - 78.47.141.18/32

[jimr1]

Ok I had a similar issue using netplan see here https://forum.virtualmin.com/t/ubuntu-22-04-switching-network-configuration-from-dhcp-to-static/116930/35 I resolved this by reverting to ubuntu 20.04 and disabling netplan … not sure but there maybe an problem with netplan

[tpnsolutions]

@suther,

I have a feeling your “floating” address is meant for “inbound” not “outbound” connections and is not actually directly assigned to your server. That’s likely while your server IP address is being detected as the one ending in “.22”.

[suther]

Did configured the IP like described by the Provider: https://docs.hetzner.com/cloud/floating-ips/persistent-configuration#ubuntu-2004

Don’t now what steps may be needed to make it also used as outbound ip.

[tpnsolutions]

@suther,

Does your network adapter actually utilize “eth0” or another naming schema? For instance my laptop which runs Ubuntu uses the naming schema of “enp4s0”… and/or are both IPs using the same adapter name as this WILL NOT work either generally speaking… Assuming you are using the documented naming schema of “eth0” then a second IP would need to be called “eth0:1” or similar which makes it a “virtual network adapter” allowing both IPs to use the same physical network adapter in the system.