misc/132553: ipfw doesnt understand ftp-data port

[Christoph Weber-Fahr]

The following reply was made to PR misc/132553; it has been noted by GNATS.

From: Christoph Weber-Fahr <cwf-ml at arcor.de>
To: Maxim Konovalov <maxim at macomnet.ru>
Cc: bug-followup at FreeBSD.org
Subject: Re: misc/132553: ipfw doesnt understand ftp-data port 
Date: Wed, 11 Mar 2009 23:35:03 +0100

 Hello,
 
 Maxim Konovalov <maxim at macomnet.ru> wrote:
 >> # ipfw add 1770 allow tcp from any to any ftp-data keep-state
 >>
 >> but now it produces
 >>
 >>  ipfw: unrecognised option [-1] ftp-data
 [...]
 > $ ipfw -n add 1770 allow tcp from any to any ftp\\-data keep-state
 > 
 > 01770 allow tcp from any to any dst-port 20 keep-state
 > 
 > works for me.
 
 Two problems with that:
 
 1. it is neither obvious nor documented that you need
     to escape the minus.
 
 The manpage says you can use names from /etc/services.
 No restrictions.  The minus sign is not a shell token
 either, so ipfw gets it as it is. Furthermore, ipfw
 can handle minus signs on various parts of its syntax
 tree, so its not a general problem.
 
 So there is no reason for the plain user to escape that.
 
 Actually, even though it might be obvious to you, I have no
 clue why actually escaping is necessary now when it wasn't
 needed before.
 
 2. it breaks compatibility with older firewall scripts.
 
 I ran against that when migrating a larger firewall rule
 set from freebsd 4.x to 6.x. That line worked quite
 nicely in freebsd 4.x. (don't know about 5.x)
 
 So I suggest fixing it, or, at least, document the problem
 in the man page.
 
 Regards
 
 Christoph Weber-Fahr