How can I make it that only approved IP addresses have access to my Ubuntu server 12.04 I only just set it up.
You can achieve this with following commands provided you have
To allow by a specific IP address use,
To allow by a specific subnet we invoke netmask and use,
To allow by a specific port and an IP address you can use,
Please refer community documentation for advance help.
/etc/hosts.deny is checked before /etc/hosts.allow, so you can go
first, we block everything from everyone,
which means only 192.168.0.2 on your local network can access ssh server on that machine.
This would be accomplished with
Depending on what you're doing with your server (and what you're serving), this will need to be (carefully) configured to permit the appropriate traffic.
There's a good tutorial on this at Ubuntu's official help website and there's also ufw (Uncomplicated Firewall) that's built in to Ubuntu to handle the basics. For example if you wanted to only permit SSH (TCP 22) access from 10.0.0.15, you'd do this:
You can also use one of several handy iptables rule generators to generate an entire iptables ruleset.
Worth noting - to catch the private address range (RFC1918) you probably want 192.168.0.0/16, -not- /8.