An e-mail firewall applies policies to e-mail messages transmitted between a first site and a plurality of second sites. The e-mail firewall includes a plurality of mail transfer relay modules for transferring e-mail messages between the first site and one of the second sites. Policy managers are used...http://www.google.fr/patents/US7127741?utm_source=gb-gplus-shareBrevet US7127741 - Method and system for e-mail message transmission
