IPShutter provides firewall protection for specific ports like ssh while allowing selective access via one-time passwords.
IPShutter is written in Perl language and requires ipchains on 2.4 kernels. Note that ipchains can be loaded as a module. IPShutter must run as root, and you may need to modify the first line of IPShutter to point to where Perl5 is located on your system. Furthermore, this software's new release, version 0.2, includes several impressive features. Most notably, configuration options are now moved to /etc/ipshutterrc, and daemonization is fixed.
In summary, if you're looking for a reliable software that helps you control the access to your server, PShutter is an excellent option. It's easy to use and highly secure. So, give it a try and ease your access control worries.
Version 0.2: N/A