# Internet service providers Main configuration box Here is a non-comprehensive list of internet service providers by countries, wich contains criteria of tolerance to self-hosting. A "no" may cause problems of the using of your server or may require you to make additional configurations. Status in brackets indicates the default behavior. A list of French and Belgian ISPs is available on the [french page](/isp_fr). ### USA | Service provider | Box (modem/router) | uPnP available | Port 25 openable | [Hairpinning](http://en.wikipedia.org/wiki/Hairpinning) | Customizable reverse DNS | Fix IP | | --- | --- | --- | --- | --- | --- | --- | | Cox | Multiple | Yes | No. Only for business class customer. | No | No | Yes, as a business class customer | | Charter | Multiple | Yes | No. Only for business class customer. | No | No | Yes, as a business class customer | | DSLExtreme | Multiple | Yes | Yes | No | No | Yes, extra charge. | ### UK | Service provider | Box (modem/router) | uPnP available | Port 25 openable | [Hairpinning](http://en.wikipedia.org/wiki/Hairpinning) | Customizable reverse DNS | Fix IP | | --- | --- | --- | --- | --- | --- | --- | | BT Internet | - | - | Yes| - | - | No | ### Brazil | Service provider | Box (modem/router) | uPnP available | Port 25 openable | [Hairpinning](http://en.wikipedia.org/wiki/Hairpinning) | Customizable reverse DNS | Fix IP | | --- | --- | --- | --- | --- | --- | --- | | Global Village Telecom | Multiple | Yes | No. Only for Fix IP| No | No | Yes, extra charge. | ### Ireland | Service provider | Box (modem/router) | uPnP available | Port 25 openable | [Hairpinning](http://en.wikipedia.org/wiki/Hairpinning) | Customizable reverse DNS | Fix IP | | --- | --- | --- | --- | --- | --- | --- | | Whizzy Internet | Multiple | Yes | Yes| Yes | Yes | Yes | If you want to add international ISPs information, please do consider [modifying this page](/write_documentation).