4-20 Firmware User Guide
PPTP example
To enable a firewall to allow PPTP traffic, you must provision the firewall to allow inbound and outbound TCP
packets specifically destined for port 1723. The source port may be dynamic, so often it is not useful to apply
a compare function upon this portion of the control/negotiation packets. You must also set the firewall to allow
inbound and outbound GRE packets, enabling transport of the tunnel payload.
From the Main Menu navigate to Display/Change IP Filter Set, and from the pop-up menu select Basic Firewall.
Select Display/Change Input Filter.
Display/Change Input Filter screen
Select Input Filter 1 and press Return. In the Change Input Filter 1 screen, set the Destination Port information
as shown below.
Select Input Filter 2 and press Return. In the Change Input Filter 2 screen, set the Protocol Type to allow GRE as
shown below.
Main
Menu
System Filter
Sets Display/Change
Filter Set
Configuration Basic
Firewall
+--#----Source IP Addr----Dest IP Addr------Proto-Src.Port-D.Port--On?-Fwd--+
+---------------------------------------------------------------------------+
| 1 0.0.0.0 0.0.0.0 TCP NC =2000 Yes No |
| 2 0.0.0.0 0.0.0.0 TCP NC =6000 Yes No |
| |
+---------------------------------------------------------------------------+
Change Input Filter 1
Enabled: Yes
Forward: Yes
Source IP Address: 0.0.0.0
Source IP Address Mask: 0.0.0.0
Dest. IP Address: 0.0.0.0
Dest. IP Address Mask: 0.0.0.0
Protocol Type: TCP
Source Port Compare... No Compare
Source Port ID: 0
Dest. Port Compare... Equal
Dest. Port ID: 1723
Established TCP Conns. Only: No