Using SSH as a login method for *NIX boxes is pretty common. One thing I am regularly asked by our dedicated server users is how to add messages that can be viewed when a user is accessing the system. Keep in mind that it would be well worth restricting root login and running SSH on a non-standard port
There are two methods for doing this, you can use just one or both depending on the desired effect.
Firstly (in time order) there is the banner which appears after a username has been typed. This is normally used to provide a warning against unauthorised access as follows:
login as: user
************************NOTICE***********************
This system is optimised and configured with security and logging as a
priority. All user activity is logged and streamed offsite. Individuals
or groups using this system in excess of their authorisation will have
all access terminated. Illegal access of this system or attempts to
limit or restrict access to authorised users (such as DoS attacks) will
be reported to national and international law enforcement bodies. We
will prosecute to the fullest extent of the law regardless of the funds
required. Anyone using this system consents to these terms and the laws
of the United Kingdom and United States respectively.
************************NOTICE***********************
To add this to your server, you will need to edit your ssh config file (/etc/ssh/sshd_config) and uncomment/add the following line: Banner /etc/banner
You will then want to create/edit the banner you have just referenced: ( pico /etc/banner)
You will need to restart the ssh daemon for this to work: ( service sshd restart)
When you login, you should now see your message displayed after you have entered a username.
The second method is MOTD (Message of the day). The difference here is that this is displayed after login has completed. Some of the most common uses depending of the numbers of users with access:
Rules for accessing files/services
A message for the next sysadmin due to monitor the box
A list of common commands and how to execute them
Anything else of use
To add a MOTD, you will need to edit the motd file : ( pico /etc/motd ), add your message and save the file, it should now be displayed on successful login. If you were to use both it would display something like this:
login as: user
************************NOTICE***********************
This system is optimised and configured with security and logging as a
priority. All user activity is logged and streamed offsite. Individuals
or groups using this system in excess of their authorisation will have
all access terminated. Illegal access of this system or attempts to
limit or restrict access to authorised users (such as DoS attacks) will
be reported to national and international law enforcement bodies. We
will prosecute to the fullest extent of the law regardless of the funds
required. Anyone using this system consents to these terms and the laws
of the United Kingdom and United States respectively.
************************NOTICE***********************user@domain.com’s password:
Last login: Sun Apr 27 14:37:24 2008 from user-22222222.domain.comYou have somehow managed to login….We are now monitoring your access,
our systems administrators have received a page to alert them of your
presense. If you are not a fully authorised user acting within your
rights then logoff immediately to prevent further action.
