ZyXEL Communications ZyWall USG 50-H Series User Manual page 277

Figure 214 Network > ALG
The following table describes the labels in this screen.
Table 101 Network > ALG
LABEL
Enable SIP ALG
Enable SIP
Transformations
Enable
Configure SIP
inactivity time
out
SIP Media
inactivity time
out
SIP Signaling
inactivity time
out
SIP Signaling
Port
Enable H.323
ALG
ZyWALL USG 50-H User's Guide
DESCRIPTION
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
page 397).
Select this to have the ZyWALL modify IP addresses and port numbers 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.
Select this option to have the ZyWALL apply SIP media and signaling inactivity time
out limits.
Use this field to set how many seconds (1~86400) the ZyWALL will allow a SIP
session to remain idle (without voice traffic) before 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.
Most SIP clients have an "expire" mechanism indicating the lifetime of signaling
sessions. The SIP user agent sends registration packets to 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).
If you are using a custom UDP port number (not 5060) for SIP traffic, enter it here.
Use the Add icon to add fields if you are also using SIP on additional UDP port
numbers.
Turn on the H.323 ALG to detect H.323 traffic (used for audio 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 26 on page 397).
Chapter 16 ALG
Chapter 26 on
277