ZyXEL 2WG Guida Utente

 Chapter 25 ALG Screen

ZyWALL 2WG User’s Guide

If the SIP client does not have this mechanism and makes no calls during the ZyWALL SIP 
timeout default (60 minutes), the ZyWALL SIP ALG drops any incoming calls after the 
timeout period. 

If no voice packets go through the SIP ALG before the timeout period (default 5 minutes) 
expires, the SIP ALG does not drop the call but blocks all voice traffic and deletes the audio 
session. You cannot hear anything and you will need to make a new call to continue your 
conversation.

Click ADVANCED > ALG to open the ALG screen. Use the ALG screen to turn individual 
ALGs off or on and set the SIP timeout. 

"

If the ZyWALL provides an ALG for a service, you must enable the ALG in 
order to perform bandwidth management on that service’s traffic.

Figure 297   ADVANCED > ALG 

The following table describes the labels in this screen.  

Table 150   ADVANCED > ALG

Enable FTP 

ALG

Select this check box to allow FTP sessions to pass through the ZyWALL. FTP (File 

Transfer Program) is a program that enables fast transfer of files, including large 

files that may not be possible by e-mail. 

Enable H.323 

ALG

Select this check box to allow H.323 sessions to pass through the ZyWALL. H.323 is 

a protocol used for audio communications over networks. 

Enable SIP 

ALG

Select this check box to allow SIP sessions to pass through the ZyWALL. SIP is a 

signaling protocol used in VoIP (Voice over IP), the sending of voice signals over 

Internet Protocol.