Ntp Commands; Application Layer Gateway (Alg) Commands - Arris NVG599 Administrator's Handbook

Administrator's Handbook

NTP Commands

set ip ntp enable [ on | off ]
Enables or disables acquiring the time of day from an NTP (Network Time Protocol) server.
set ip ntp server-address server_address
set ip ntp alt-server-address alt_server_address
Specifies the NTP server(s) to use for time updates. The NTP server-address and alt-server-address values can
be entered as DNS names as well as IP addresses.
set ip ntp update-period minutes
Specifies how often, in minutes, the gateway should update the clock. Default is 1440.

Application Layer Gateway (ALG) Commands

These commands allow you to enable or disable the router's support for a variety of application layer gateways
(ALGs). An application layer gateway (ALG) is a NAT component that helps certain application sessions to pass
cleanly through NAT. Each ALG has a slightly different function based on the particular application's protocol-
specific requirements.
An internal client first establishes a connection with the ALG. The ALG determines if the connection should be
allowed or not and then establishes a connection with the destination computer. All communications go
through two connections – client to ALG and ALG to destination. The ALG monitors all traffic against its rules
before deciding whether or not to forward it. Because the ALG is the only address seen by the public Internet,
the internal network is concealed. In some situations, it may be desirable to disable some of the ALGs.
set ip alg esp-enable [ on | off ]
Turns the ESP (Encapsulating Security Payload) ALG for file transfers on or off. Default is on.
set ip alg esp-setup-timeout value
Specifies the timeout value for the ESP ALG setup. Default is 180.
set ip alg esp-stream-timeout value
Specifies the timeout value for the ESP ALG streaming. Default is 300.
set ip alg ftp-enable [ on | off ]
Turns the FTP (File Transfer Protocol) ALG for file transfers on or off. Default is on.
set ip alg h323-enable [ on | off ]
Turns the H323 ALG for audio, video, and data communications across IP-based networks on or off. Default is
on.
set ip alg pptp-enable [ on | off ]
Turns the PPTP (Point-to-Point Transfer Protocol) ALG for authentication on or off. Default is on.
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