Date: Wed, 30 Jan 2002 09:23:29 -0800 (PST) From: Jan-Peter Koopmann <j.koopmann@akctech.de> To: freebsd-gnats-submit@FreeBSD.org Subject: misc/34458: 4.5S/sshd forwarding problems Message-ID: <200201301723.g0UHNTn24434@freefall.freebsd.org>
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>Number: 34458 >Category: misc >Synopsis: 4.5S/sshd forwarding problems >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Wed Jan 30 09:30:00 PST 2002 >Closed-Date: >Last-Modified: >Originator: Jan-Peter Koopmann >Release: 4.5 Stable >Organization: >Environment: FreeBSD dajump.nextra.de 4.5-STABLE FreeBSD 4.5-STABLE #2: Wed Jan 30 10:37:15 CET 2002 root@dajump.nextra.de:/usr/obj/usr/src/sys/MYKERNEL i386 >Description: I use ssh to tunnel tcp connections like IRC and http from my Windows client to a FreeBSD 4.5 Stable machine. Since I upgraded from 4.4R to 4.4S this does not work anymore. Symptoms: The ssh connection works normally but tunneled connection does not. Example with IRC: On my client I connect to localhost:6667 which is correctly tunneled via my FreeBSD machine to the IRC server. The connection request reaches the server. tcpdump shows that the IRC server even answers the request. The irc client however is unable to establish the connection. After around 60 seconds we see a "PING timeout" message from the IRC server. Funny enough THIS message is even transmitted through the tunnel to the client. We crosschecked with differen irc clients, SSH clients and protocols (we tried the same thing with tunneling HTTP), Windows version, client-machines, FreeBSD versions and machines. Everything works up to FreeBSD 4.4R. After that: Nothing. To us this seems to be a problem of dropped packets. To exclude client-program problems we tried connecting to the tunnel with telnet. THIS WORKS! >How-To-Repeat: 1. Setup an ssh connection with tunnel/forward of port 6667 to an irc-server:6667. Client: Windows 2000 or XP. Server: FreeBSD 4.5R. 2. Try to establish a connection on your Windows client with an irc program (e.g. mirc) to localhost:6667. Wait for the timeout. 3. Then try to establish a connection on your Windows client using telnet to the same port and be astonished! >Fix: Downgrade to 4.4R. Sad but true. :-) >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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