This is due to ssh's flexible argument parsing. If you skip the hostname, them something else is interpreted as the hostname. > Am 09.01.2014 um 18:43 schrieb bryan hunt <picsolvebryan at gmail.com>: > > Yes, called as you describe, SSH works correctly (it Forwards Agent). Quirky! > > But, called the way I was doing, everything but Agent Forwarding works. > > Strange. Looking further, I found another odd behaviour. > > ssh -o User=vagrant -o Hostname=127.0.0.1 -p 2222 -o Compression=yes -o StrictHostKeyChecking=no -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o IdentitiesOnly=yes -i /Users/bryanhunt/.vagrant.d/insecure_private_key -o ForwardAgent=yes -o LogLevel=DEBUG "" "/bin/sh -c 'git clone git at bitbucket.org:bryan_picsolve/poc_docker.git /home/vagrant/poc_dockerddd? " > > Note how I added the empty quoted string in the hostname position. > > SSH Agent Forwarding works if I add that empty quoted string. > > If I remove the empty quoted string, the git checkout is executed, but prompts for authentication. > > I would expect SSH to completely succeed, or completely fail to execute the command - rather than have the side channel (SSH agent) fail or succeed based upon how I express the command line arguments. > > This is a stock version of the ssh command on OSX. > > The checksum is: > > MD5 (/usr/bin/ssh) = 35caacee333ebae93d4087ca349738e4 > > Perhaps another OSX user could verify this behaviour? > > Regards, > > Bryan Hunt > > >> On 9 Jan 2014, at 17:21, Markus Friedl <mfriedl at gmail.com> wrote: >> >> You pass it as an option. >> >> But ssh is called like >> >> $ ssh [options] hostname [command] >> >> >> >> >> >>> Am 09.01.2014 um 16:21 schrieb bryan hunt <picsolvebryan at gmail.com>: >>> >>> >>> I don?t understand, in the second example, "ssh -o HostName=127.0.0.1 ?, is the very first argument to the program? >>> >>> >>> >>>> On 9 Jan 2014, at 13:21, Markus Friedl <mfriedl at gmail.com> wrote: >>>> >>>> The 2nd example misses the required hostname argument. >>>> >>>> >>>> >>>> >>>>> Am 09.01.2014 um 13:32 schrieb bryan hunt <picsolvebryan at gmail.com>: >>>>> >>>>> >>>>> Trying to get SSH agent forwarding working for a popular open source configuration management system called Ansible. >>>>> >>>>> I?ve had some unexpected behaviour, the only cause of which I can find is how I express the command line arguments. >>>>> >>>>> http://stackoverflow.com/questions/20952689/vagrant-ssh-agent-forwarding-how-is-it-working?noredirect=1#comment31511341_20952689 >>>>> >>>>> In summarise: >>>>> >>>>> In the first instance I can create a SSH connection, and and execute a remote git clone (via SSH), the Agent Forwarding works, and I am not prompted for credentials: >>>>> >>>>> ssh vagrant at 127.0.0.1 -p 2222 \ >>>>> -o Compression=yes \ >>>>> -o StrictHostKeyChecking=no \ >>>>> -o LogLevel=FATAL \ >>>>> -o StrictHostKeyChecking=no \ >>>>> -o UserKnownHostsFile=/dev/null \ >>>>> -o IdentitiesOnly=yes \ >>>>> -i /Users/bryanhunt/.vagrant.d/insecure_private_key \ >>>>> -o ForwardAgent=yes \ >>>>> "/bin/sh -c 'git clone git at bitbucket.org:bryan_picsolve/poc_docker.git /home/vagrant/poc_dockera' " >>>>> Cloning into '/home/vagrant/poc_dockera'... >>>>> >>>>> In the second instance I express the arguments differently ( -o HostName=127.0.0.1 -o User=vagrant ), and Agent Forwarding doesn?t seem to work: >>>>> >>>>> ssh -o HostName=127.0.0.1 -o User=vagrant -p 2222 \ >>>>> -o Compression=yes \ >>>>> -o StrictHostKeyChecking=no \ >>>>> -o LogLevel=FATAL \ >>>>> -o StrictHostKeyChecking=no \ >>>>> -o UserKnownHostsFile=/dev/null \ >>>>> -o IdentitiesOnly=yes \ >>>>> -i /Users/bryanhunt/.vagrant.d/insecure_private_key \ >>>>> -o ForwardAgent=yes \ >>>>> "/bin/sh -c 'git clone git at bitbucket.org:bryan_picsolve/poc_docker.git /home/vagrant/poc_dockerb' " >>>>> /bin/sh -c 'git clone git at 127.0.0.1's password: >>>>> >>>>> The client side SSH is: >>>>> >>>>> OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011 >>>>> >>>>> The server side SSH is: >>>>> >>>>> OpenSSH_5.9p1 Debian-5ubuntu1.1, OpenSSL 1.0.1 14 Mar 2012 >>>>> >>>>> >>>>> Have any of the list members got an insight into this behaviour ? >>>>> >>>>> Thanks in advance, >>>>> >>>>> Bryan Hunt >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>>>> openssh-unix-dev mailing list >>>>> openssh-unix-dev at mindrot.org >>>>> https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev > > _______________________________________________ > openssh-unix-dev mailing list > openssh-unix-dev at mindrot.org > https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
