Because a hardened OS is often the last line of defense in the event of a security compromise, hardening of all servers (internal and external) is vitally important.
If a malicious user is able to penetrate perimeter defenses, a hardened server provides the final layer for the security of the data assets and functionality of the servers. Host security also provides the first line of defense against internal threats, which may have equal or higher probability of occurrence as external threats.
It is important to note that hardening is not a panacea for security. It is just another layer in a good security model. By definition, any machine that is accessible on a network and running services (i.e. pretty much any server) is potentially insecure.
Ward Solutions is highly experienced in the provisioning of technical services based on multi-vendor Microsoft, Unix, Linux and OpenVMS environments. We have specialist engineers in all variants of UNIX including Solaris, HPUX and Tru64.