To use Xmanager, which ports should I allow on my firewall?

You should open the following TCP/UDP ports.

• From remote host to local PC (Inbound): 
  - TCP 6000 ~ 6010 for Xmanager
  - *TCP 16001 for Gnome only
• From local PC to remote host (Outbound): 
  - UDP 177 for XDMCP
  - TCP 512, 513, 514, 23, 22 for Xstart

*Note: Gnome may fail to login or logout if TCP 16001 port is not allowed.