Chapter 19 ALG

The following table describes the labels in this screen.

Table 96 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. Enabling the SIP ALG also allows you to

 

use the application patrol to detect SIP traffic and manage the SIP

 

traffic’s bandwidth (see Chapter 28 on page 437).

 

 

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.

 

 

Enable Configure

Select this option to have the ZyWALL apply SIP media and signaling

SIP Inactivity

inactivity time out limits.

Timeout

 

 

 

SIP Media

Use this field to set how many seconds (1~86400) the ZyWALL will

Inactivity

allow a SIP session to remain idle (without voice traffic) before

Timeout

dropping it.

 

If no voice packets go through the SIP ALG before the timeout period

 

expires, the ZyWALL deletes the audio session. You cannot hear

 

anything and you will need to make a new call to continue your

 

conversation.

 

 

SIP Signaling

Most SIP clients have an “expire” mechanism indicating the lifetime of

Inactivity

signaling sessions. The SIP user agent sends registration packets to

Timeout

the SIP server periodically and keeps the session alive in the ZyWALL.

 

If the SIP client does not have this mechanism and makes no calls

 

during the ZyWALL SIP timeout, the ZyWALL deletes the signaling

 

session after the timeout period. Enter the SIP signaling session

 

timeout value (1~86400).

 

 

SIP Signaling

If you are using a custom UDP port number (not 5060) for SIP traffic,

Port

enter it here. Use the Add icon to add fields if you are also using SIP

 

on additional UDP port numbers.

 

 

Enable H.323

Turn on the H.323 ALG to detect H.323 traffic (used for audio

ALG

communications) and help build H.323 sessions through the ZyWALL’s

 

NAT. Enabling the H.323 ALG also allows you to use the application

 

patrol to detect H.323 traffic and manage the H.323 traffic’s

 

bandwidth (see Chapter 28 on page 437).

 

 

Enable H.323

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

Transformations

embedded in the H.323 data payload.

 

You do not need to use this if you have a H.323 device or server that

 

will modify IP addresses and port numbers embedded in the H.323

 

data payload.

 

 

H.323 Signaling

If you are using a custom TCP port number (not 1720) for H.323

Port

traffic, enter it here.

 

 

Additional H.323

If you are also using H.323 on an additional TCP port number, enter it

Signaling Port

here.

for

 

Transformations

 

 

 

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ZyWALL USG 50 User’s Guide