Server not allowed to connect to mirrorlist

NethServer Version: 7.9
Module: yum
4 installations behind this public IP.

  • The Scapegoat.
  • one designed to stay into LAN and providing services only on LAN
  • one designed to become (one day, maybe) a public server, hosted somewhere, with services not needing LAN access
  • the OpenProject test installation.

These installations do not have the same DNS servers, but all of them are allowed to find

The internal services only, neverthless, is usually saying this

Could not retrieve mirrorlist error was
14: curl#7 - "Failed connect to; Connection refused"

Is there any way to understand why the installation offended the mirrorlist deliverer? Is there any fingerprint which can be changed for being more… accepted by the mirrorlist?
For… some period seem blacklisted.

Do you use IPS? It may block yum/curl…

Thanks for your hint, but currently no.

Modules currently installed.

Hell of a boy!
My nice appliance answered “too many connections, dude!” More than 1k. Currently upgraded session limit to 1.5k (max 8192 sessions for single host as system limit).

Nethserver mirror infastructure is not guilty.

I’ll rephrase in a more simple way…
The installation which had the problem was already using all of the 1000 connections par-host allowed by the firewall in front of the installation.
Problem was solved increasing to 1500 allowed connections the specific server (it hosts a quite… nosy Zabbix server), then yum update ran without any issue. Connection was refused by the appliance, not from the Nethserver mirrorlist server. Now connection is lower (less than 500) so I reduced to 1200 the max connections for the host.