Step 1
Make sure in your /etc/mongodb.conf file you have the following line,
bind_ip = 0.0.0.0
Step 2
Add iptables rules to control the incoming and outgoing traffic for mongo. Here is a sample command if you have the default ports for mongo.
$ sudo iptables -A INPUT -s 198.61.168.XXX,166.78.113.XX -p tcp --destination-port 27017 -m state --state NEW,ESTABLISHED -j ACCEPT $ sudo iptables -A OUTPUT -d 198.61.168.XXX,166.78.113.XX -p tcp --source-port 27017 -m state --state ESTABLISHED -j ACCEPT
Here 198.61.168.XXX and 166.78.113.XX are the IP from where you want to access the mongodb.