Adding new WFE server from DMZ to existing SharePoint Farm which is there in corporate LAN

Hi,

We Have requirement where we need to add new WFE server to DMZ zone, so that we can deploy public facing application on this WFE server. However this WFE server would be added to existing SharePoint farm (having 2 WFE, 2 APP  & 1 DB server) which is configured in corporate LAN.

Please note that existing farm will have intranet application running on it.

would like to know what are the port we need to open to corporate LAN so that new WFE  can be added to existing farm.

Also would like to know any specific configuration I need to take care. 

Thanks & Best Regards,

Safder