Resolved Curl error: (6) Couldn't resolve host name

[floh]

Server operating system version

Debian GNU/Linux 10 \n \l

Plesk version and microupdate number

Version 18.0.56 Update #1

Hi,

I'm facing multiple issues with the Plesk Server that it cannot resolve while performing daily tasks, such as creating backups. The recurring problem seems to be related to Curl's inability to resolve.

For instance, here's an example of the issue I'm encountering:

Unable to delete the incomplete remote backup. Error: Failed to exec pmm-ras: Exit code: 124: Transport error: unable to check file existence: Curl error: (6) Couldn't resolve host name: Last FTP request: Last FTP response:

I've already double-checked the nameserver settings, and they appear to be correct. I can successfully ping and use the dig command for everything, including the host that automated processes (like backups) are failing on.

Do you have any insights into what might be causing this issue? Any assistance with troubleshooting would be greatly appreciated.

Best regards,
Floh

 

[TorbHo]

Please check the settings of /etc/resolv.conf

Try adding

nameserver 127.0.0.1

nameserver 8.8.8.8

and comment everything else like

# nameserver 127.0.0.53

 

[floh]

You mean /etc/resolv.conf should have those both lines:

nameserver 127.0.0.1
nameserver 8.8.8.8

Not sure if it matters, Plesk is running as primary Nameserver (synced with 2 secondary nameserver on different machine) for the Domains hosted by Plesk. Does it matters?

I'll try that at weekend because currently there is a live-event running now.

Best regards
Floh

 

[TorbHo]

You mean /etc/resolv.conf should have those both lines:

Yes. Comment out all other lines with nameserver x.x.x.x

8.8.8.8 is Google DNS Server.
It is intended for testing purpose if 127.0.0.1 still does not work.

Not sure if it matters, Plesk is running as primary Nameserver (synced with 2 secondary nameserver on different machine) for the Domains hosted by Plesk. Does it matters?

bind9 should work with nameserver 127.0.0.1 for resolv.conf

 

[danami]

@TorbHo I'm not sure if this is related to your problem but there is a bug after updating Plesk to 18.0.56 where the Plesk panel interface PHP secure curl functions do not work properly unless the Plesk panel interface is restarted. We are seeing this issue with our Plesk extensions as the curl functions like license checks, Maxmind downloads don't work unless the panel interface is restarted. You can fix this using the command:

systemctl restart sw-engine && systemctl restart sw-cp-server

 

[floh]

Hi, sorry for the late reply. The issue has been resolved, and it was due to the wrong nameserver (authoritative), which I replaced with the correct one (recursive). Since then, all DNS-related issues have been resolved.

Thank you for your replies.
Best regards,
Floh

 

[chrysllercs]

How did you manage to resolve it? I'm facing the same issue with cURL 6 error in daily tasks like creating backups. The error occurs randomly, and I noticed that the problem persists even though I'm already using Google DNS. This is evident because when I run the command 'ping google.com' in the terminal, I still get 'Temporary failure in name resolution' intermittently.

 

[floh]

Hi, you're facing different issue than mine. My DNS-Server requested the wrong NS so it was not temporary failure in name resolution.

Maybe you should start there:

Fix "Temporary Failure In Name Resolution" Error

Learn how to troubleshoot and fix the "Temporary failure in name resolution" error, including checking DNS configuration and using public DNS servers.

www.redswitches.com

Also check if network works well, maybe there is some problem.. Also double-check you don't have IP-address conflict (try ARPing).

I'm sorry that I cannot help you much.

Best regards
Floh

 

[chrysllercs]

Hi, you're facing different issue than mine. My DNS-Server requested the wrong NS so it was not temporary failure in name resolution.

Maybe you should start there:

Fix "Temporary Failure In Name Resolution" Error

Learn how to troubleshoot and fix the "Temporary failure in name resolution" error, including checking DNS configuration and using public DNS servers.

www.redswitches.com

Also check if network works well, maybe there is some problem.. Also double-check you don't have IP-address conflict (try ARPing).

I'm sorry that I cannot help you much.

Best regards
Floh

Thank you for the help. Indeed, my mistake was different from yours. My issue was in "/etc/systemd/resolved.conf". The person managing the network had mistakenly added a space where it shouldn't be, in the first IPv6.

Incorrect: (single space)

DNS=8.8.8.8 8.8.4.4 2001:4860:4860:: 8888 2001:4860:4860::8844

Correct:

DNS=8.8.8.8 8.8.4.4 2001:4860:4860::8888 2001:4860:4860::8844

Days of issues due to a space.

 

[floh]

Hi, glad you found out and fixed the issue.