12.7.6 OpenSSH Configuration Files and Commands

sftp [@hostname]

sftp option that specifies the remote system

sftp [username]

sftp option that specifies the user account on the remote system

UsePAM

/etc/ssh/sshd_config option that enables the Pluggable Authentication Modules interface between sshd and the system

ListenAddress

/etc/ssh/sshd_config option that gives the addresses that SSH should use when listening for requests

AllowUsers

/etc/ssh/sshd_config option that lists users allowed to use SSH

DenyUsers

/etc/ssh/sshd_config option that lists users not allowed to use SSH; overrides AllowUsers entry

Protocol

/etc/ssh/sshd_config option that spcifies which protocols SSH allows when accessing the SSH server

Port

/etc/ssh/sshd_config option that specifies the port number

PermitRootLogin

/etc/ssh/sshd_config option that specifies whether users can log in as root over SSH

ssh [commands]

ssh option that runs the commands on the remote system but displays the results on the local machine

ssh [hostname]

ssh option that specifies the SSH server name and could include a domain name

ssh -l

ssh option that specifies the user account on the server

PasswordAuthentication

/etc/ssh/sshd_config option that disables password authentication when set to no

User

/etc/ssh/ssh_config or ~./ssh_config option that automatically logs in with the specified user name instead of requesting a username

StrictHostKeyChecking

/etc/ssh/ssh_config or ~./ssh_config option that determines whether SSH clients can accept keys from SSH server not previously accessed

Port

/etc/ssh/ssh_config or ~./ssh_config option that specifies the port that SSH uses

Protocol

/etc/ssh/ssh_config or ~./ssh_config option that specifies which protocols SSH allows when accessing the SSH server

CheckHostIP

/etc/ssh/ssh_config or ~./ssh_config option that verifies that the supplied key matches the IP address of the server when set to yes

slogin

command that allows access to a shell on a remote computer; identical to the ssh command; supported only for backwards compatibility

get [file_name]

command that copies a file from the ftp server

cdup

command that traverses up a directory

cat [keyfile].pub >> /etc/ssh/ssh_known_hosts

command to manually add new keys

scp

command used to encrypt and copy files from a remote system over the network

ssh

command used to make a secure conection from the SSH client to the SSH server; overrides entries in /etc/ssh/ssh_config and ~/.ssh/config files

service sshd

command used to manage the current state of the SSH daemon on the server

sftp

command used to transfer files securely from ftp servers

which

command used to verify if a package is installed on the system

/etc/ssh/ssh_config

file that configures OpenSSH for all users on the client system

/etc/ssh/sshd_config

files used to configure the SSH daemon on the server system

scp [destination/filename]

scp option that specifies the location and name of the new file

scp [@hostname:remotefile]

scp option that specifies the remote system and remote file

scp [username]

scp option that specifies the user account on the remote system

service sshd stop

service sshd option that halts a running daemon

service sshd status

service sshd option that shows the status of a single daemon

service sshd start

service sshd option that starts a daemon that is not currently running

service sshd restart

service sshd option that stops and restarts a daemon

~/.ssh_config

user-specific hidden file which can override the configuration in /etc/ssh/ssh_config

/etc/ssh/ssh_known_hosts or ~/.ssh/known_hosts

where the keys of previously accessed servers are stored