Proxy server with authentication not working at command line

Ok, I totally forgot about -vvv :-) Here is the output:

OpenSSH_5.6p1, OpenSSL 1.0.0a 1 Jun 2010
debug1: Reading configuration data /home/echox/.ssh/config
debug1: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Executing proxy command: exec /usr/bin/corkscrew http-proxy.proxy.tld 8080 somehost.tld 22
debug1: permanently_drop_suid: 1000
zsh: No such file or directory
[..]
ssh_exchange_identification: Connection closed by remote host

The key is the line with ssh_connect: needpriv 0. I forgot to add my user to the network group in /etc/group. The connection worked with root and after adding the user to network it works also for him now.

Connections without corkscrew did work before. Does anybody have an idea where this "security" setting is stored? I can't find anything in the arch linux wiki, /etc/, man ssh and the corkscrew source / corkscrew documentation which checks for the network group.

From my Linux workstation, the only application that can access the internet are a) Firefox (using its own proxy configuration and authentication stored in Firefox), as well as applications running in a Windows VM (Note - the windows VM is a domain member and the user authenticates against the domain when logging in)

Solution option: Run a web proxy on your windows VM. Setup your system to use that instance as your proxy.

Since your Windows VM is already authenticated and traffic is allowed through it, setting up a SOCKS proxy on that VM instance will centralized your authentication needs. If it is just for you and your boxes, this should be fine and is probably fairly straightforward.

Piggybacking on this idea is to get an SSHD daemon running on the Windows VM so you can do things like SSH SOCKS tunnels from your other boxes through the VM:

ssh -D 1080 windows-user@windows-vm

For those apps that may have problems or where you don't want to reconfigure the apps, you can make use of sshtunnel, which will setup iptables rules to route traffic. Works for Linux and Mac systems.

If you need to avoid installing a proxy on the Windows VM itself, you can setup a Squid proxy box configured to authenticate itself against the windows AD. A guide on doing that located here:

Solution option: Squid Proxy Authenticated via AD/NTLM

http://techmiso.com/1934/howto-install-squid-web-proxy-server-with-active-directory-authentication/ (dead link)

Another NTLM proxy solution, though I think this one actually runs on a Windows machine:

Solution option: NTLM proxy http://cntlm.sourceforge.net/