Webshield Blocking Unrelated Ports

Issue:

Webshield bocking unrelated connections and it leads to different issues, like connection timeouts for different services (FTP, MySQL, webserver and so on). The issue goes away when webshield is disabled.

Environment

• Imunify360 6.3.* and lower
• Webshield
• Any supported OS
• Any supported panel

Solution

Explicitly reserve the following ports:

echo '52220-52239' > /proc/sys/net/ipv4/ip_local_reserved_ports

Restart Imunify360 service and also the 3rd-party services have been affected, like eg  MySQL.

systemctl restart imunify360

Cause

It's a known behavior with the WebShield which redirects the traffic to ports/connections that are not used by itself, therefore may block unrelated connections. The definitive fix for the issue already shipped with Imunify360 6.4 release.

Useful links

https://docs.imunify360.com/webshield/#imunify360-webshield