A FoIP server mediating fax communication between gateways and enterprise backend systems. The gateways are VoIP capable, connected to the PSTN and the enterprise network, and mediate between the PSTN fax call and fax over IP calls. The FoIP Server mediates between the FoIP calls and enterprise backend systems, such as message transfer agent (MTA), Customer Relationship Management CRM, document management, web services, mainframe, or a specialized application requiring faxing capabilities.