The SSH connection to a remote system is initiated with the following command:
- ssh [-?] [-h] [-b loopback-address] [-p port] [-C] [-j interval]
[user@]host [command]
- -?, -h: Display a brief help text about the available arguments
- -b: Specifies the loopback address to be used. This option is important in the context of ARF.
- -p: Specifies the port to be used. If the port is not specified here, the default is TCP port 22.
- command: The SSH client either starts an interactive shell on the remote system or it can execute a single command. If no command is entered, the interactive shell starts.
- user: User name for logging in to the remote system. If you do not explicitly enter a user name here, then the user name for your current local session is used for logging in at the LCOS CLI.
- -C: If this option is specified, the SSH client uses the zlib algorithm to attempt to negotiate a method for data compression with the remote system. If the remote system does not support compression, then the data is transmitted uncompressed. The use of compression is generally worthwhile only for slow connections (e.g. ISDN). With fast connections, the performance loss from the additional overhead due to compression tends to be greater than the gain from reduced data amounts.
- -j interval: If the connection to the remote system is routed via a NAT router or a firewall, it may be worthwhile to leave the connection running permanently. With an interactive SSH session, data is not transferred at all at certain phases, which can lead to disconnection because of timeouts. In such cases the SSH client can regularly transmit keep-alive packets. These are irrelevant to the remote station, but they inform the gateway that the connection is still being used. This argument specifies the interval in seconds for transmitting keep-alive packets. The keep-alive packets are only transmitted when the SSH client is not sending other data to the remote system.