Administration Manual ip500pbxw – English
109
Enter the host IP address and Subnet mask
Select the direction,
Inbound
,
Outbound
or
Both
Select
Apply
Save the new configuration
Restart the system.
Application Level Gateways
There are certain applications that NAT and Firewall configurations cannot manage. In many cases, ALGs (Application
Level Gateways) are needed to translate and transport packets correctly. An ALG provides a service for a specific
application such as FTP (File Transfer Protocol). Incoming packets are checked against existing NAT rules or Firewall
filters, IP addresses are evaluated and detailed packet analysis is performed. If necessary, the content of a packet is
modified, and if a secondary port is required, the ALG will open one. The ALG for each application does not require any
configuration.
ALG support is provided for the following applications. If support is required for additional applications, security triggers can
be configured for these.
Application
TCP Port
UDP Port
AIM (AOL Instant Messenger)
5190
N/A
FTP (File Transfer Protocol)
21
N/A
IKE (Internet Key Exchange)
N/A
500
ILS (Internet Locator Service)
389 (+1002)
N/A
MSN (Microsoft Networks)
1863
N/A
PPTP (Point-to-Point Tunnelling
Protocol)
1723 N/A
RSVP (Resource Reservation
Protocol)
N/A N/A
L2TP (Layer 2 Tunnelling Protocol)
N/A
1701
SIP (Session Initiation Protocol)
5060
5060
