On servers protected by a firewall, the following ports must not be blocked to ensure proper operation of Plesk and accessibility of Plesk-managed services.

Service name Ports used by service
Administrative interface of Plesk over HTTPS TCP 8443
Administrative interface of Plesk over HTTP TCP 8880 *
Web server and Plesk Updater TCP 80, TCP 443
FTP server TCP 20, 21, 990
SSH (secure shell) server TCP 22
SMTP (mail sending) server TCP 25, TCP 465
POP3 (mail retrieval) server TCP 110, TCP 995
IMAP (mail retrieval) server TCP 143, TCP 993
MySQL server TCP 3306
MS SQL server TCP 1433
Tomcat Java service TCP 9080, 9008
Licensing Server connections TCP 443
Domain name server UDP 53, TCP 53
Plesk upgrades and updates TCP 8447

Warning: If you use Presence Builder, do not block inbound connections to port 8880, otherwise Presence Builder will not function.