From owner-freebsd-hackers Thu Oct 24 17:50:28 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8316D37B401 for ; Thu, 24 Oct 2002 17:50:26 -0700 (PDT) Received: from april.chuckr.org (april.chuckr.org [66.92.147.143]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2A5CB43E6E for ; Thu, 24 Oct 2002 17:50:25 -0700 (PDT) (envelope-from chuckr@chuckr.org) Received: from april.chuckr.org (localhost [127.0.0.1]) by april.chuckr.org (8.12.6/8.12.5) with ESMTP id g9P0m0li017724 for ; Thu, 24 Oct 2002 20:48:00 -0400 (EDT) (envelope-from chuckr@chuckr.org) Received: from localhost (chuckr@localhost) by april.chuckr.org (8.12.6/8.12.5/Submit) with ESMTP id g9P0lxdj017647 for ; Thu, 24 Oct 2002 20:47:59 -0400 (EDT) X-Authentication-Warning: april.chuckr.org: chuckr owned process doing -bs Date: Thu, 24 Oct 2002 20:47:58 -0400 (EDT) From: Chuck Robey To: FreeBSD Hackers List Subject: X11 display problem Message-ID: <20021024203033.T353-100000@april.chuckr.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG To be frank, I just solved a problem that a number of folks asked me about, and I just wanted to get it into the FreeBSD mailing list archive, so that others that hit the problem can find the solution. You can probably safely hit 'delete' now, if you haven't got a problem getting xterms from remote machines to open on your local display. [search keywords: X11 display remote security ssh xterm] The problem scenario: you've finally gotten around to upgrading your old machine to the latest FreeBSD version. Works fine, but suddenly, you can no longer get remote X11 apps to pop local displays. No, it's NOT an ssh problem. Yes, I know there's a dozen reasons why it *could* be ssh, or even a FreeBSD kernel (ipfw) type problem, but that's not this one either. Why am I so sure? Because I used the ports/net/ethereal port to scope out the communications. The remote machine tries to open a link on tcp/6000 (like all good little x11 programs should do) but your local box responds with an RST, killing the connection before it gets started. At that point, ssh hasn't even woken up yet, so it couldn't be that. Can't be an X11 security problem either; either one would show some additional tcp traffic. What's the problem? Not FreeBSD at all, it's the new version of XFree86 that you upgraded to when you upgraded FreeBSD. There is a server option, -nolisten-tcp. If you invoke it, the Xserver doesn't open the normal tcp socket to listen on 6000. That's not changed, it's the startx(1) shell script that some folks use to start X that's been changed. The script now has a -listen_tcp (note the difference with the Xserver negative option -nolisten_tcp). If you fail to give the -listen_tcp option to startx, then the default is for startx to begin the Xserver with the -nolisten_tcp option, killing the socket that remote apps rely on. The fix that I've found so far is either to start X with xdm (which doesn't have that default off), to start startx with the -listen_tcp option, or to edit the startx script to remove the -nolisten_tcp arg to the Xserver invocation. ---------------------------------------------------------------------------- Chuck Robey | Interests include C & Java programming, FreeBSD, chuckr@chuckr.org | electronics, communications, and signal processing. New Year's Resolution: I will not sphroxify gullible people into looking up fictitious words in the dictionary. ---------------------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message