First, the real IP Masquerade info is found at:

• Linux IP Masquerade mini HOWTO

I much appreciate the effort put into the "Linux IP Masquerade mini HOWTO". In fact, all of the HOWTOs! Thanks!

From ipmasq's readme:

NAME
     ipmasq - determine a network device's IP address & set Firewall &
     Masquerade rules.

SYNOPSIS
     ipmasq command [masquerade_device]	[masquerade_ip]

DESCRIPTION
     This command is a /bin/sh script that determines  a  network
     device's dynamic IP address & sets Firewall & Masquerade rules
     according to the recommendations in the "Linux IP Masquerade mini
     HOWTO".

SPECIAL NOTE
     This version of ipmasq assumes ipfwadm - i.e., 2.0 & maybe early
     2.1 kernels.  I will put out an ipchain version when I upgrade my
     machine to 2.2.

ANONYMOUS FTP
     To	obtain ipmasq:
	     prompt> ftp ftp.xmission.com
	     prompt> user: anonymous
	     prompt> password: [user@domain]
	     prompt> cd	/pub/users/b/bgeer
	     prompt> bin
	     prompt> get ipmasq.tgz
	     prompt> quit
     Much obliged to Sebastien Baena (maccoy@softhome.net) for the
     suggestion to add the "bin" command.  I can't count the times
     I've inadvertently downloaded in ASCII mode by mistake!