Firewall and Port Issues
To achieve full access to all services provided by their hosting accounts, clients require an open or appropriately configured internet connection providing access to and from the ports handling the concerned services.
Occasionally, hosting clients accessing their server from behind a corporate or personal firewall can be thwarted by overly restrictive or badly planned firewall rules. This is particularly likely in cases where the connection to their server is being attempted via an employer provided internet connection. In many such cases the encountered blocking is fully intended, since the corporate connection is not being provided for that purpose, and the network administrator will understandably not be inclined to modify the existing firewall rules.
In cases of corporate firewalls, some network administrators may be prepared to modify existing firewall rules to accommodate client requirements, but many, quite reasonably, will not.
In cases where a personal firewall is running on the client's local machine, the client will need to investigate the method of rule configuration and make the required rule set modifications locally.
The following table provides a quick reference of the minimum port access required of an internet connection to enable access to the respective services.
|Service||Port No.||Port Type|
|HTTP (HyperText Transfer Protocol)||80||TCP|
|FTP (File Transfer Protocol)||20||TCP|
|SSH (Secure Shell)||22||TCP|
|POP3 (Post Office Protocol)||110||TCP|
|IMAP (Internet Message Access Protocol)||143||TCP|
|SMTP (Simple Mail Transport)||25||TCP|
|SMTPS (Legacy Secure - Officially URD)||465||TCP|
A complete listing of all transport protocol ports is available at the IANA Service Name and Transport Protocol Port Number Registry.