alfreddatakillen/callhome

SSH Call Home Script

CONFIGURE YOUR PUBLICLY ACCESSIBLE SERVER:

1.

Add this to /etc/ssh/sshd_config:

ClientAliveInterval 5
ClientAliveCountMax 3
GatewayPorts yes

2.

Add user on the publicly accessible server:

useradd --system --home-dir /etc/ssh/revssh --no-log-init --create-home --shell /bin/false revssh

3.

Clean up the revssh user's home dir:

rm -Rf /etc/ssh/revssh/* /etc/ssh/revssh/.*

4.

Create authorized keys file for the revssh user:

mkdir /etc/ssh/revssh/.ssh

Now, copy your non-publicly available server's id_rsa.pub file to /etc/ssh/revssh/.ssh/authorized_keys

Fix the permissions:

chown -R revssh:revssh /etc/ssh/revssh/.ssh

CONFIGURE YOUR SERVER BEHIND A FIREWALL:

Edit the callhome.sh variables in the file top.

Run callhome.sh every minute with a cronjob:

* * * * * /home/alfred/callhome/callhome.sh