This tutorial shows you how to remove the Debian signature/version info from packages such as Apache, Postfix or SSH. There are various reasons to remove the signature (and therefore hide that you are using Debian/a specific version). The most important one is about security. When a hacker knows the distro you are using, he can search for well-known security issues and start an attack against them. If he doesn’t know the distro in use, chances to not find any security holes are much larger.