From owner-freebsd-questions@FreeBSD.ORG Wed Nov 19 12:47:07 2003 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7BA6F16A4CE for ; Wed, 19 Nov 2003 12:47:07 -0800 (PST) Received: from dshsmsg2.dshs.wa.gov (dshsmsg2.dshs.wa.gov [147.56.131.10]) by mx1.FreeBSD.org (Postfix) with SMTP id ED44A43FD7 for ; Wed, 19 Nov 2003 12:47:05 -0800 (PST) (envelope-from FELTIRC@dshs.wa.gov) Received: from 147.56.131.20 by dshsmsg2.dshs.wa.gov with ESMTP (DSHS MMS SMTP Relay (MMS v4.7);); Wed, 19 Nov 2003 12:47:05 -0800 X-Server-Uuid: 1a548dfa-be79-11d4-99cf-009027d0d054 Received: by dshsmsg1.dshs.wa.gov with Internet Mail Service ( 5.5.2657.72) id ; Wed, 19 Nov 2003 12:47:06 -0800 Message-ID: <496C6CA6ABA8DD4AB652EA39C9E5540D2938B8@dshs-exch1> From: "Feltis, Ralph C." To: "'Marty Landman'" , "'freebsd-questions@freebsd.org'" Date: Wed, 19 Nov 2003 12:47:03 -0800 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2657.72) X-WSS-ID: 13A509431327086-01-01 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Subject: RE: Network messaging X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Nov 2003 20:47:07 -0000 Currently, my use of FreeBSD is limited. I are using it for network-based imaging using Frisbee (http://www.emulab.net/software.php3, great program btw). One computer is serving up images using 4.8, and the clients boot using a customized 4.7 CD. The clients connect to the server and, depending on what port they choose, pull down a specific install image. The clients have to log into FreeBSD, and ideally, would receive a MOTD that tells them which image is on which port. Now, I know it's possible to simply edit the MOTD and create a new CD, but as often as the images change, it wouldn't be very practical. That's where my idea of sending some kind of network data to the server when the client logs on and then the server replying with the port to image information comes in. I can't imagine that I need anything complex, as I am only working in the console with the clients. Any ideas? Ralph -----Original Message----- From: Marty Landman [mailto:MLandman@face2interface.com] Sent: Wednesday, November 19, 2003 12:24 PM To: Feltis, Ralph C.; 'freebsd-questions@freebsd.org' Subject: Re: Network messaging At 02:51 PM 11/19/2003, Feltis, Ralph C. wrote: >Is it possible to set some type of simple messaging system between networked >FreeBSD machines? For example, client A pings client B, and then client B >sends some prespecified text reply to client A. Ralph, it's certainly possible to setup something a bit more sophisticated using ftp and cron to store and routinely check for the presence of a file, or in an intranet situation, e.g. if Apache is installed and both boxes have http access you could use a CGI script. The details of the implementation would/should be based on the detailed need which you haven't given. This raises a question I'm curious about which is in this scenario you could easily run into the need for semaphores. I've run into this problem running MS-DOS execs on networked windoz boxes (stop that snickering plz) and could clearly see the updates stepping on each other's toes. What is available on fbsd by way of protecting e.g. file writes? FWIW I understand the standard flock mechanism I've used with Perl on nix servers isn't foolproof, but surely something in the system is....? Marty Landman Face 2 Interface Inc 845-679-9387 Sign On Required: Web membership software for your site Make a Website: http://face2interface.com/Home/Demo.shtml