O'Reilly logo

ScreenOS Cookbook by Sunil Wadhwa, Joe Kelly, Ken Draper, David Delcourt, Vik Davar, Stefan Brunner

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

11.1. View the List of Available ALGs

Problem

You want to view the list of available and enabled ALGs on a ScreenOS gateway.

Solution

Based on the release of ScreenOS, a number of ALGs are enabled in the factory default configuration. You can view the list of available ALGs on a ScreenOS gateway with the following code:

	Internal_fw-> get alg

To limit the output list to the ALGs that are enabled on the ScreenOS gateway, use the following syntax:

	Internal_fw-> get alg | include enabled

Discussion

Based on the release of ScreenOS, a number of ALGs are enabled in the factory default configuration. The list of ALGs available on the ISG-2000 platform as of ScreenOS 6.0r2 is:

	nsisg2000-> get alg
	DNS      ALG : enabled
	FTP      ALG : enabled 
	H323     ALG : enabled
	HTTP     ALG : enabled
	MGCP     ALG : enabled
	MSRPC    ALG : enabled
	PPTP     ALG : disabled
	REAL     ALG : enabled
	RSH      ALG : enabled
	RTSP     ALG : enabled
	SCCP     ALG : enabled
	SIP      ALG : enabled
	SQL      ALG : enabled
	SUNRPC   ALG : enabled
	TALK     ALG : enabled
	TFTP     ALG : enabled
	XING     ALG : enabled
	nsisg2000->

Table 11-1 briefly describes the applications representing the ALGs indicated in the preceding code snippet. In the table, the trigger port specifies the TCP or UDP destination port of the first packet in a flow that will activate ALG inspection of the entire conversation.

Table 11-1. ALG application detail

ALG name

Application name

Trigger port

Description

DNS

Domain Name System

UDP/53 and TCP/53

DNS queries ride on UDP/53 and return an IP address response when provided ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required