Chapter 19 ALG

•See Section 19.3 on page 357 for ALG background/technical information.

19.1.3Before You Begin

You must also configure the firewall and enable NAT in the ZyWALL to allow sessions initiated from the WAN.

19.2 The ALG Screen

Click Configuration > Network > ALG to open the ALG screen. Use this screen to turn ALGs off or on, configure the port numbers to which they apply, and configure SIP ALG time outs.

Figure 215 Configuration > Network > ALG

The following table describes the labels in this screen.

Table 98 Configuration > Network > ALG

LABEL

DESCRIPTION

Enable SIP ALG

Turn on the SIP ALG to detect SIP traffic and help build SIP sessions

 

through the ZyWALL’s NAT.

 

 

Enable SIP

Select this to have the ZyWALL modify IP addresses and port numbers

Transformations

embedded in the SIP data payload.

 

You do not need to use this if you have a SIP device or server that will

 

modify IP addresses and port numbers embedded in the SIP data

 

payload.

 

 

 

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ZyWALL USG 20/20W User’s Guide