Gerardo Lamastra
2001-Nov-13 18:00 UTC
Intermittent port forwarding problems openssh 2.9.2p and up
Hi, I have configured ssh for port forwarding local 8080 to out company web proxy server. # ssh -L 8080:proxy:8080 myname at ssh-host I've tried the configuration by using # telnet localhost 8080 and it works fine. But whenever I try to use it with any http browser, it just fails. I investigated the problem with Ethereal and I've noticed that packets travel on loopback interface, arrive over ssh-host, but there only the 3-way handshake is performed and no extra data is sent to the proxy. It's like data is "lost", and the proxy timeouts. The same behavior happened using different ssh clients (openssh-2.9.9 on Linux and ttssh for Windows), different server (different release of openssh (2.9 and 2.5 mainly) on different architectures (Linux & OpenBSD)); different web browsers (lynx, links,netscape, explorer). I've also tried different proxy servers (netscape proxy server and squid) I tried it with other protocols (Ex. using imap access to our corporate mail hub) using Netscape and it seems to work fine. This seems very similar to the problem reported by mcurtis9 at csc.com.au on 2001-09-25 2:09:57. Thanks for your attention. -- Gerardo Lamastra Centro Sicurezza Be-Secure Telecom Italia LAB Via Reiss Romoli 274 - 10148 Torino Tel. 011 228-6586 Fax. 011 228-6360