From owner-freebsd-net@FreeBSD.ORG Mon Apr 30 12:29:11 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 125A216A407 for ; Mon, 30 Apr 2007 12:29:11 +0000 (UTC) (envelope-from jhary@unsane.co.uk) Received: from unsane.co.uk (www.unsane.co.uk [85.233.185.162]) by mx1.freebsd.org (Postfix) with ESMTP id 7BEAA13C469 for ; Mon, 30 Apr 2007 12:29:10 +0000 (UTC) (envelope-from jhary@unsane.co.uk) Received: from [192.168.10.217] (150.117-84-212.staticip.namesco.net [212.84.117.150]) (authenticated bits=0) by unsane.co.uk (8.14.0/8.14.0) with ESMTP id l3UBxWC0057865 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 30 Apr 2007 12:59:33 +0100 (BST) (envelope-from jhary@unsane.co.uk) Message-ID: <4635DA11.7080401@unsane.co.uk> Date: Mon, 30 Apr 2007 12:59:13 +0100 From: Vince User-Agent: Thunderbird 1.5.0.10 (X11/20070327) MIME-Version: 1.0 To: "Abraham K. Mathen" References: In-Reply-To: X-Enigmail-Version: 0.94.0.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org Subject: Re: Why can't I sendto() to 127.255.255.255 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 30 Apr 2007 12:29:11 -0000 Abraham K. Mathen wrote: > NOTE : A copy of this message was sent to freebsd-hackers also. > Apologies for the separate mails. > > Hello freebsd-net, > I wrote a short program (on FreeBSD 6.0), that attempts > to call sendto() on a UDP socket, with 127.255.255.255 as > the destination address. It failed - with errno 49 (EADDRNOTAVAIL). > Setting SO_BROADCAST and IP_ONESBCAST did not help. > > After examining > - various RFC's, > - source code under /usr/src/sys/netinet/ and > - archives of freebsd-hackers & freebsd-net, > I have not been able to determine the reason. > > Is it possible to successfully sendto() on a UDP socket > with 127.255.255.255 as the destination address? If yes, > how can that be done. > > Specific questions : > ---------------------------------------------------------- > - Is it correct to understand that 127.255.255.255 is the > directed network broadcast address for net 127? If yes, > which RFC specifies that? > > - If not, is 127.255.255.255 considered to be a host > address? If yes, which RFC specifies that? > ---------------------------------------------------------- > As far as I am aware the only RFC's that define the 127.0.0.0/8 block are rfc3330 which states, 127.0.0.0/8 - This block is assigned for use as the Internet host loopback address. A datagram sent by a higher level protocol to an address anywhere within this block should loop back inside the host. This is ordinarily implemented using only 127.0.0.1/32 for loopback, but no addresses within this block should ever appear on any network anywhere and rfc1122 which says: { 127, } Internal host loopback address. Addresses of this form MUST NOT appear outside a host. I would interpret this as 127.0.0.0/8 are all loopback host addresses, but I'd be happy to be corrected. Vince > Could you please help me understand this? > > > sincerely > > Mathen > (Abraham K. Mathen) > > _________________________________________________________________ > Mega Airfare Sale. Click here Now. > http://ss1.richmedia.in/recurl.asp?pid=18 > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"