Management Through SSH

SSH (Secure Shell) is a secure alternative to the ancient Telnet program/protocol. Telnet (and SSH) allows a user to connect to a remote server, and enables the users to use a command line interface to execute commands (manage the server).

Where Telnet is relatively limited in its functionality, SSH has a bunch of features which enables the user to do much more. The SSH protocol has the possibility to tunnel traffic through an SSH connection (read: tunnel). The big advantage is that everything going through the tunnel is heavily encrypted (which is good).

The tool best known to use SSH is SFTP (FTP over SSH). A secure alternative of the 'old' (in plaintext communicating) File Transfer protocol.

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SSH Connection to Juniper Devices

While in the mids of my Juniper exam preparation I ran into a problem with my Apple equipment. Managing the Juniper firewall (SSG5 in this case) with SSH was not possible from OSX. The connection itself would work, but after entering the password the connection was closed by the remote host (the firewall).
Trying this from a Windows laptop (with SecureCRT) everything worked as expected.

Some searching revealed that this is an OpenSSH bug. To manage your Juniper with SSH from OSX you need to add a parameter to the ssh command (or edit the SSH config file).

Parameter to add:

-o ControlMaster=auto
e.g. ssh willem@127.0.0.1 -o ControlMaster=auto

Or add the following line to the global SSH config (/etc/ssh_config) or the user config (~/.ssh/config).

ControlMaster auto

Juniper has a knowledgebase article (KB12409) on the issue.