From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1EegFo-0000ox-2L for qemu-devel@nongnu.org; Tue, 22 Nov 2005 17:04:44 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1EegFh-0000mN-Hh for qemu-devel@nongnu.org; Tue, 22 Nov 2005 17:04:42 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1EegFh-0000mH-8M for qemu-devel@nongnu.org; Tue, 22 Nov 2005 17:04:37 -0500 Received: from [81.187.81.51] (helo=smtp.aaisp.net.uk) by monty-python.gnu.org with esmtp (TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA:24) (Exim 4.34) id 1EegFg-0004KI-Nk for qemu-devel@nongnu.org; Tue, 22 Nov 2005 17:04:37 -0500 Received: from [81.187.40.226] (helo=[81.187.40.226]) by smtp.aaisp.net.uk with esmtps (TLSv1:AES256-SHA:256) (Exim 4.43) id 1EegFf-0006YJ-7S for qemu-devel@nongnu.org; Tue, 22 Nov 2005 22:04:35 +0000 Message-ID: <438395F0.5010000@hermes.cam.ac.uk> Date: Tue, 22 Nov 2005 22:04:32 +0000 From: Richard Neill MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: user-net -redir working? [problem located] Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel > Re: User-net not working: > > > Disabling the Nagle algorithm (i.e., enabling TCP_NODELAY) or typing a > > lot of garbage just to fill the buffer with enough data can help, > > also. > > > > And IIRC, netcat has a UDP mode as well. I see no reason for this to > > happen, but is there any chance it's using UDP by default, and you're > > only redirecting TCP? > > > > Good luck! > > Thanks for your message. > > I think that -redir really is broken: I've also been unsuccessful in > trying to make it work using an FTP server on a Windows guest, and using > the SSH server on a knoppix guest. Has anyone here ever had success with > it? It also fails on hosts with 2 different versions of Mandrake. > > Anyway, I've taken your suggestion, and run both ends with ethereal. > Here's what I did: > > > HOST (Linux); > qemu -cdrom /dev/cdrom -boot d -user-net -redir tcp:2200::22 > > GUEST (Knoppix): > Boot up, then start sshd. Verify that I can indeed do ssh > root@localhost, and that PermitRootLogin is yes in sshd_config. > > Then, start ethereal (on the "any" interface) > > > HOST: > Start ethereal (on the "any" interface") > ssh -p 2200 root@localhost > > At this point, ssh just stalls. It's obviously waiting for something, > but not known what. I get no output at all from it. Can you try "ssh -p 2200 root@ I've run into this several times dealing with the -redir function, especially since localhost resolves as 127.0.0.1. On my Solaris host with a linux guest, the packet arriving showed up as 127.0.0.1, which ended up with the same behavior as you're describing. --------------- Dear Ben, Good guess! That's an ingenious bit of debugging, and it now works perfectly. I suppose that now means 3 things need to be done: 1)Figure out *why* it doesn't work. It's definitely QEMU-specific, since if I run 2 separate netcat processes on the host, I have no problem. I'd be interested to know why this occurs. In particular, is it a problem with the user-net stuff on the host, or a problem with the guest? 2)Fix it... :-) 3)Document this on the website as a known bug, so Google can find it. Currently, anyone using an earlier version will just think that qemu is broken. It hasn't worked since at least 0.6.1, although I can't tell you about earlier versions. I suspect that I am not up to the task of (2), so I must defer to the experts... Best wishes, Richard