Issue Fail2Ban error after Plesk update

[OverWolf]

Hi,
I've updated the version of Plesk from 17.5.3 to 18.0.29 without any evident problem.
Now, I'm on 18.0.29 u2 and after some test I've seen in F2B log that there are some errors when I stop or restart fail2ban service.
This is an example :

2020-08-23 20:26:41,418 fail2ban.actions [2598]: NOTICE [recidive] Flush ticket(s) with iptables-ipset-proto6-allports
2020-08-23 20:26:41,427 fail2ban.utils [2598]: Level 39 7xx7xxxxcafx -- exec: iptables -w -F f2b-recidive
2020-08-23 20:26:41,427 fail2ban.utils [2598]: ERROR 7xx7xxxxxafx -- stderr: 'iptables: No chain/target/match by that name.'
2020-08-23 20:26:41,427 fail2ban.utils [2598]: ERROR 7xx7xxxxafx -- returned 1

These errors aren't present in 17.5.3 and now after I have read and look at f2b github, I think that there is a problem or a solution with plesk.
I can see that iptables ruleset is created, and that f2b-recidive is present; but there is some other service that delete that ruleset before I can send the action-stop to iptables with f2b.

Now, I'm here to ask if there is a service or other process that in Plesk 18.0.29 delete (or flush) iptables rules so the chain don't exists anymore and I have those errors.

Thank you

 

[OverWolf]

Hi,
other problem is reported in this article : Fail2ban extension hangs in Plesk: iptables: Too many links.\n but I have the same problem with Obsidian

2020-08-26 11:46:54,158 fail2ban.utils [3169]: Level 39 7xx11xxx7xx8 -- exec: iptables -w -D INPUT -p tcp -j f2b-recidive
iptables -w -F f2b-recidive
iptables -w -X f2b-recidive
2020-08-26 11:46:54,158 fail2ban.utils [3169]: ERROR 7xx11xxx7xx8 -- stderr: 'iptables: Too many links.'
2020-08-26 11:46:54,158 fail2ban.utils [3169]: ERROR 7xx11xxx7xx8 -- returned 1
2020-08-26 11:46:54,159 fail2ban.actions [3169]: ERROR Failed to stop jail 'recidive' action 'iptables-allports': Error stopping action Jail('recidive')/iptables-allports