Subject: x2go client issues using HTTP proxy

From: Nimesh Jethwa <[email-masked]>
Date: Mon, 08 Feb 2016 11:35:59 -0500

Package: x2goclient
Version: 4.0.5.0-0

When trying to connect to a session using HTTP proxy, it fails the first
time with the below message in an error dialog.

"Socket error: disconnected"

When connecting to the same session the second time within 30 secs, the
connection goes through and I am logged into my virtual desktop. I am
able to replicate this issue several times.

Below is the output of the client running in debug mode (with the above
scenario captured) -

==========

x2go-INFO-8> "Starting connection to server:
desktop.a1200.virtualorgs.net:80"
x2go-DEBUG-../src/onmainwindow.cpp:2758> Starting new ssh connection to
server:"desktop.a1200.virtualorgs.net":"80" krbLogin: false
x2go-DEBUG-../src/sshmasterconnection.cpp:168> SshMasterConnection, host
"desktop.a1200.virtualorgs.net"port 80user "superuser"useproxy
trueproxyserver "desktop.a1200.virtualorgs.net"proxyport 80
x2go-DEBUG-../src/sshmasterconnection.cpp:205> Starting SSH connection
without Kerberos authentication.
x2go-DEBUG-../src/sshmasterconnection.cpp:209> SshMasterConnection,
instance SshMasterConnection(0x10d8030)  created. 
x2go-DEBUG-../src/sshmasterconnection.cpp:445> SshMasterConnection,
instance SshMasterConnection(0x10d8030)  entering thread. 
x2go-DEBUG-../src/sshmasterconnection.cpp:481> libssh not initialized
yet. Initializing.
x2go-DEBUG-../src/sshmasterconnection.cpp:559> Created HTTP proxy
socket: -1

x2go-DEBUG-../src/sshmasterconnection.cpp:564> Connected to HTTP proxy
server: "desktop.a1200.virtualorgs.net":80

x2go-DEBUG-../src/sshmasterconnection.cpp:581> "Cannot connect to
desktop.a1200.virtualorgs.net:80" - "Socket error: disconnected"
x2go-ERROR-2> "Connection error: Cannot connect to
desktop.a1200.virtualorgs.net:80: Socket error: disconnected"
x2go-DEBUG-../src/sshmasterconnection.cpp:711> SshMasterConnection,
instance SshMasterConnection(0x10d8030)  waiting for thread to finish. 
x2go-DEBUG-../src/sshmasterconnection.cpp:715> SshMasterConnection,
instance SshMasterConnection(0x10d8030)  thread finished. 
x2go-DEBUG-../src/sshmasterconnection.cpp:722> SshMasterConnection,
instance SshMasterConnection(0x10d8030)  finished destructor. 
x2go-INFO-8> "Starting connection to server:
desktop.a1200.virtualorgs.net:80"
x2go-DEBUG-../src/onmainwindow.cpp:2758> Starting new ssh connection to
server:"desktop.a1200.virtualorgs.net":"80" krbLogin: false
x2go-DEBUG-../src/sshmasterconnection.cpp:168> SshMasterConnection, host
"desktop.a1200.virtualorgs.net"port 80user "superuser"useproxy
trueproxyserver "desktop.a1200.virtualorgs.net"proxyport 80
x2go-DEBUG-../src/sshmasterconnection.cpp:205> Starting SSH connection
without Kerberos authentication.
x2go-DEBUG-../src/sshmasterconnection.cpp:209> SshMasterConnection,
instance SshMasterConnection(0x10d3580)  created. 
x2go-DEBUG-../src/sshmasterconnection.cpp:445> SshMasterConnection,
instance SshMasterConnection(0x10d3580)  entering thread. 
x2go-DEBUG-../src/sshmasterconnection.cpp:498> libssh already
initialized.
x2go-DEBUG-../src/sshmasterconnection.cpp:559> Created HTTP proxy
socket: 13

x2go-DEBUG-../src/sshmasterconnection.cpp:564> Connected to HTTP proxy
server: "desktop.a1200.virtualorgs.net":80

x2go-DEBUG-../src/sshmasterconnection.cpp:792> cserverAuth
x2go-DEBUG-../src/sshmasterconnection.cpp:807> state: 1

x2go-DEBUG-../src/sshmasterconnection.cpp:966> Password authentication
requested.

x2go-DEBUG-../src/sshmasterconnection.cpp:657> User authentication OK.
x2go-DEBUG-../src/onmainwindow.cpp:2853> SSH connection established.
x2go-DEBUG-../src/onmainwindow.cpp:3120> Continue normal X2Go session

==========

I am able to connect on the first try with the same HTTP proxy server
settings using Putty and even NoMachine v3.5. But for X2GO, it's always
on the second try.

I am currently using X2GO 4.0.5.0-0x2go1+git20160126.1112+jessie.main.1,
Debian GNU/Linux 8, libssh4-0.6.3-4+deb8u1, libc6-2.19-18+deb8u1.

Also, I can replicate this issue on Debian 8 - v4.0.3.1-4 and Windows 7
- v4.0.5.0.

Any help here would be greatly appreciated.

Thanks,
Nimesh