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Custom SSH Banner with script

Hi all,

I want to create a SSH header for all my servers that will include some scripts.

For example it will display internal and external IP as well as memory usage.

I understand that you must edit the /etc/motd file to do this.

I have edited mine:

Code:

The programs included with the Debian GNU/Linux system are free software;

the exact distribution terms for each program are described in the

individual files in /usr/share/doc/*/copyright.



Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent

permitted by applicable law.



Current external IP: "$IP_SCRIPT"

I am new to scripts and wonder what's the process of getting this script to work

The IP_SCRIPT for example will use the curl -s and ifconfig commands to output results to the banner

I don't know if you can run a script from /etc/motd, but here's what I've done to achieve the same thing:
Basically, just call a script from users ~/.bashrc, it will print out when they login.
I always create a custom file "/tux/conf/profile/bash.sh" which is sourced from ~/.bashrc - this is because I want to keep all custom configuration in my own directory-structure, away from system.

Below is my "/tux/conf/profile/bash.sh", with some basic config and a script that is used for servers using "ucarp" - that is they share one virtual up and the one that holds that ip is the "live" web-server.

Code:

# Script to check for virtual ip, and server status

# But only for login shell



# Default prompt

PS1="[\u@\H:\w]$ " 



# Custom aliases

alias l='ls -la'



# PATH for sudo-users 

export PATH=$PATH:/sbin:/usr/sbin:/usr/local/sbin:ih/sbin



# Script to check server status

# But only for login shell

case "$-" in *i*)    # This is the line that makes this script run only for login-shells

        if [[ $(ip addr show eth0 |grep "10.64.6.8") ]]; then

                echo -e "This server is \e[01;31m MASTER \e[0m"

        else

                echo "This server is Standby"

        fi

        echo ""

esac

Quote:

Originally Posted by Ali3n0id (Post 5320993)

Hi all,
I want to create a SSH header for all my servers that will include some scripts. For example it will display internal and external IP as well as memory usage. I understand that you must edit the /etc/motd file to do this.

I have edited mine:

Code:

The programs included with the Debian GNU/Linux system are free software;

the exact distribution terms for each program are described in the

individual files in /usr/share/doc/*/copyright.



Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent

permitted by applicable law.



Current external IP: "$IP_SCRIPT"

I am new to scripts and wonder what's the process of getting this script to work The IP_SCRIPT for example will use the curl -s and ifconfig commands to output results to the banner

Look at the ForceCommand option in sshd_config:
http://linux.die.net/man/5/sshd_config

It *MAY* do what you're after, but use sparingly. If I remember correctly, I tried this once, and it DID let me execute things upon login, but it negated what I tried to do from the command line. For example, just logging in, things worked fine. If you tried doing "ssh user@host "/some/script.sh"", then the results may not be right...since you're FORCED to run one script first, before ANYTHING else.

might be slightly different on your system, i use Suse (opensuse and SLES).
look in file etc/ssh/sshd_config
for #Banner
uncomment it and do something like "Banner /etc/ssh_banner.txt"
where /etc/ssh_banner.txt is what you want displayed as a banner.

for executing script after logon,
in suse at the end of the /etc/bash.bashrc file which gets executed during logon there is

Code:

# And now let us see if there is e.g. a local bash.bashrc

# (for options defined by your sysadmin, not SuSE Linux)

#

case "$is" in

bash) test -s /etc/bash.bashrc.local && . /etc/bash.bashrc.local ;;

ksh)  test -s /etc/ksh.kshrc.local  && . /etc/ksh.kshrc.local ;;

zsh)  test -s /etc/zsh.zshrc.local  && . /etc/zsh.zshrc.local ;;

ash)  test -s /etc/ash.ashrc.local  && . /etc/ash.ashrc.local

esac

test -s /etc/sh.shrc.local && . /etc/sh.shrc.local

in /etc/bash.basrc.local and csh.cshrc.local is where i had all my admin stuff, in one spot.
I would put a call to whatever you want to happen in there.

one thing i always hated and never found out, is what the chronological process is when you log on to linux and whether distributions differ. after your password is accepted, then I know files like /etc/bash.bashrc and /etc/profile are sourced, and further things get run like if remote desktop and graphics like gdm and xdm are kicked off. But i would love to know that process in detail.

that case is not necessary:

Code:

test -s /etc/$is.${is}rc.local && . /etc/$is.${is}rc.local

will do the job

Thank you all very much - the ForceCommand was exactly what I needed.

Now to customise this script to insanity.