Our online connection diagnostic system tries to figure out which services
are accessible to you and inform you of the results. It does that by attemping
to connect, from your computer, to the outbound port(s) associated with the
service(s) you're trying to access, to check if a firewall or a router is blocking
your connection.

Outbound ports are used whenever you try to connect to a server, like
a website or a mail server. Firewalls and routers are very often configured
to block some outbound ports, this is to deny your access to the specific
services that they don't want you to use. The diagnostic system on this website
is designed to see if this is the case, and report back to you