"PGP’s Universal Gateway Email is the company’s
gateway encryption (and decryption) application. To build a
transparent secure e-mail system an organization runs a virtual
appliance made up of PGP Universal Server and Universal Gateway
Email. This can run on a hardened version of Linux on one of
several specific server hardware configurations from vendors
including Dell, HP and IBM, or it can take the form of a virtual
machine running on VMware ESX.
"The appliance is connected between the corporate mail server
and the corporate firewall, and when it receives outgoing e-mail
messages from the mail server it kicks in to action. The first
things the encryption application has to do is decide which
messages to encrypt and find the public keys belonging to the
recipients of those messages that need to be encrypted. This
information is provided by the PGP Universal Server. Its role is to
manage and apply rules and policies for encryption, based on
factors including the destination, the sender, or even the contents
of the message. Account creation, group management and policy
enforcement can be automated by integrating Active Directory, Lotus
Notes/Domino directories or other LDAP directories with the
Universal Server."