From outside network, I can use the web interface of Citrix but when I
click on the application. It times out. It is interesting that if I add a
hardware router between Linux Firewall and Internet connection. It works.
Internet ---- Linux firewall ---- Citrix (Doesn't work)
Internet ---- Cheap Hardware Router with built-in firewall (DMZ to Linux) ---- Linux firewall ---- Citrix (Works)
Any idea? I only know that if go through the router, I can connect to the Citrix by using exteriior IP. If just go through the Linux firewall, the exterior IP doesn't work. Is the "router back" function causing the problem? How to set it?