Issue Problem with /etc/network/interfaces and 2 additional IPv4 on Ionos server

[Servus]

Hi @ Plesk friends,
4 weeks ago I migrated Plesk Obsidian 18.0.33 with Ubuntu 20.04.2 on Ionos dedicated server and Cloud Panel.
Important is the very last point. In real it is a Cloud server (BUT) with dedicated fixed environment, it's a dedicated server in Cloud administration.
To realize own name server (ns1.domain.com) I have 2 additional IPv4 and the main IPv4, all this name server is working fine. I also added 3 IPv6 to network/interfaces.
This nameserver environment I use without problems since years.

To add the IPv4 I used the help+support articles by Ionos for dedicated server. But the network failed (ifup: failed to bring up eth0:0)
eth0 is the main IPv4
eth0:0 is the 1st additional IPv4
eth0:1 is the 2nd additional IPv4
Interesting is it works. All IPs v4 and v6 are accessible in Plesk and used for webhosting, but with a failed network ! ! ! ! !
This is the amazing Ionos way, network service is down, but IPs are working.
The amazing Plesk way is: You can add IPs over Plesk Panel, without adding them in Ubuntu, they are working. First I always add the IPs in Plesk Panel, then I realize, oh damn, I have something forgotten, adding them in OS first. Since Ubuntu 14 it's always the same. But it works...
Only one point is not working, in the actual environment of the last weeks!
Every 12 hours the access of IPs and so for the whole server including SSH is lost. I can only restart the server over Cloud Panel and then it works again for the next 12 hours. In logs I only get the messages that there are resolving problems. I opened a support ticket in Ionos without results.

Then I used the support article for CLOUD SERVER. And now network is running successfully.
After reload all IP addresses in PLESK Panel the main server IPv4 , which is always printed in bold letters is not bold, but the first additional IPv4 is shown now in bold letters.
That's crazy, isn't it? And:
The problem with loosing access every 12 hours still exists.

On my old server with Ubuntu 18.04 I used a network/interfaces configuration which was in no support article, with configuring iface eth0 inet dhcp what you normally shouldn't use together in a configuration with eth0:0. Don't know to take the risk and add it to /interfaces/ once again? .

Actual configuration:

 

[n0fear]

Hi @ Plesk friends,
4 weeks ago I migrated Plesk Obsidian 18.0.33 with Ubuntu 20.04.2 on Ionos dedicated server and Cloud Panel.
Important is the very last point. In real it is a Cloud server (BUT) with dedicated fixed environment, it's a dedicated server in Cloud administration.
To realize own name server (ns1.domain.com) I have 2 additional IPv4 and the main IPv4, all this name server is working fine. I also added 3 IPv6 to network/interfaces.
This nameserver environment I use without problems since years.

To add the IPv4 I used the help+support articles by Ionos for dedicated server. But the network failed (ifup: failed to bring up eth0:0)
eth0 is the main IPv4
eth0:0 is the 1st additional IPv4
eth0:1 is the 2nd additional IPv4
Interesting is it works. All IPs v4 and v6 are accessible in Plesk and used for webhosting, but with a failed network ! ! ! ! !
This is the amazing Ionos way, network service is down, but IPs are working.
The amazing Plesk way is: You can add IPs over Plesk Panel, without adding them in Ubuntu, they are working. First I always add the IPs in Plesk Panel, then I realize, oh damn, I have something forgotten, adding them in OS first. Since Ubuntu 14 it's always the same. But it works...
Only one point is not working, in the actual environment of the last weeks!
Every 12 hours the access of IPs and so for the whole server including SSH is lost. I can only restart the server over Cloud Panel and then it works again for the next 12 hours. In logs I only get the messages that there are resolving problems. I opened a support ticket in Ionos without results.

Then I used the support article for CLOUD SERVER. And now network is running successfully.
After reload all IP addresses in PLESK Panel the main server IPv4 , which is always printed in bold letters is not bold, but the first additional IPv4 is shown now in bold letters.
That's crazy, isn't it? And:
The problem with loosing access every 12 hours still exists.

On my old server with Ubuntu 18.04 I used a network/interfaces configuration which was in no support article, with configuring iface eth0 inet dhcp what you normally shouldn't use together in a configuration with eth0:0. Don't know to take the risk and add it to /interfaces/ once again? .

Actual configuration:

Could you fix this problem in the meantime?

 

[Brujo]

Could one of you fix this problem in the meantime?

 

[n0fear]

Could one of you fix this problem in the meantime?

Me not, i was quite hopefull, as i used the support article for CLOUD SERVER now and the ips where there even after reboot, but now just some minutes ago, the whole server is down again, as the ip adresses are not there anymore... could not even login or ssh, had to reboot over console, all working again.... IONOS is no big help @ phone... "we cant do anything bout root / dedicated servers..." damn... will write a mail now. Anyone any idea?

 

[n0fear]

What i found out, on a Server L i could Add additional IP Adresses to eth0:0 and eth0:1 and that server works without problems since days now. On a Server XXL it seams not to be possible to add Adresses to eth0:0 and eth0:1 - it always adds them to eth0... i could not get it to work there even after reinstall... what server are yours that make problems?

 

[Brujo]

Typ: Dedicated Server XL with 2 * V4 & 2 * V6 IP Adresses
Ionos Support wasnt helpfull and even the knowledgebase examples seems not to work as expected.
So I tested several configs and ended up with one which seems now to be stable since 1 week withou losing IP Adresses

 

[n0fear]

I could get it to work on a XL and a L Server! On the XXL it was impossible to add ips to eth0:0 and eth0:1 what i did (and what is wrong in the documentation there!) i added main ip as dhcp and the extra ip as eth0:0 and eth0:1 since than it works - but the image of the XXL Server seems to be broken, as it was impossiblöe to add anything to eth0:0 only to eth0

 

[Emmir Teyer]

I have the same problem, and I have not found the solution for almost a week, it is a dedicated XL server in ionos and it crashes every 12 hours, the only thing I could do was create an alternative solution with crontab, which consists of restarting the network service every 8 hours, creating a sh script and running systemctl restart networking.service from it.

 

[carlosarmando85]

Hello,
If anyone having the IONOS issue with Dedicated Servers please check the output and let me know If you have an error here:

sudo networkctl status

 

[carlosarmando85]

Possible Solution
I've found this solution after days of trying different configurations without luck,
hopefully, this works for you as well. IONOS Dedicated Server

Inside your
/etc/netplan/ directory

you will find a file, in my case is: 50-cloud-init.yaml (it may be different on yours)

Open the file it may look like this:

network:
    ethernets:
        eth0:
            dhcp4: true
    version: 2

Add this line: critical:true, this will designate the connection as “critical to the system”, meaning that special care will be taken to not release the assigned IP when the daemon is restarted.

Example:

network:
    ethernets:
        eth0:
            dhcp4: true
            critical: true
    version: 2

Save the file and run:

sudo netplan generate
sudo netplan apply

P.S.

Check if your file located here
/etc/cloud/cloud.cfg.d/99-disable-network-config.cfg

Has this option:
network: {config: disabled}

If the file doesn't exist or doesn't have this option the changes you made to the netplan file will not be saved after a reboot.