IPShutter

PShutter is a software that allows you to securely firewall off ports and selectively enable access with a one-time password. This means that you don't have to worry about unauthorized access to your server from untrusted sources. For instance, if you want to log into the server from a friend's house, you can easily pull out a list of one-time passwords and point your web browser at a URL that contains one password. Once you do that, the server will allow the ssh connections from your friend's IP address for five minutes. Any connections made during that time period will stay up indefinitely.

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.