Date: Sun, 17 Feb 2002 01:20:01 -0800 (PST) From: "Crist J. Clark" <crist.clark@attbi.com> To: freebsd-bugs@FreeBSD.org Subject: Re: misc/35022: network broadcast addresses may be used for communications with the system just as well as if it was her own. Message-ID: <200202170920.g1H9K1o72227@freefall.freebsd.org>
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The following reply was made to PR misc/35022; it has been noted by GNATS.
From: "Crist J. Clark" <crist.clark@attbi.com>
To: Igor M Podlesny <poige@morning.ru>
Cc: freebsd-gnats-submit@FreeBSD.ORG
Subject: Re: misc/35022: network broadcast addresses may be used for communications with the system just as well as if it was her own.
Date: Sun, 17 Feb 2002 01:14:58 -0800
On Sun, Feb 17, 2002 at 03:51:23PM +0700, Igor M Podlesny wrote:
[snip]
> > But there was mention of another behavior that is a bug. You _can_
> > establish a TCP connection to a FreeBSD machine with the destination
> > being the broadcast address. This is oh so Very Very Bad. And it
> > breaks the Standard (the Standard being everyone's favorite, RFC1122),
>
> > 4.2.3.10 Remote Address Validation
>
> > ...
>
> > A TCP implementation MUST silently discard an incoming SYN
> > segment that is addressed to a broadcast or multicast
> > address.
>
> yep.
>
> BTW it declares TCP only?
No, for IP datagrams in general,
For most purposes, a datagram addressed to a broadcast or
multicast destination is processed as if it had been
addressed to one of the host's IP addresses;
As for UDP, it says nothing specific about how to handle incoming
datagrams with the broadcast address as the destination (it's up to
the application). However, it does mention,
UDP is used by applications that do not require the
level of service of TCP or that wish to use communications
services (e.g., multicast or broadcast delivery) not available
from TCP.
--
Crist J. Clark | cjclark@alum.mit.edu
| cjclark@jhu.edu
http://people.freebsd.org/~cjc/ | cjc@freebsd.org
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