Djigzo
Djigzo offers open source products that allow companies to automatically secure email and protect against unauthorized access of email both in transit and at rest.
http://www.djigzo.com
Sophos
Sophos
http://www.sophos.com/en-us/products/encryption/safeguard-mailgateway.aspx
Security
Security
http://www.security.nl/artikel/27054/1/Opensource_e-mail_encryptie_gateway_Djigzo_beschikbaar.html
Mcafee
Mcafee email gateway is a comprehensive email security solution. it blocks spam with over 99% accuracy, delivers the industry’s most comprehensive capabilities for email data loss prevention, and provides integrated, policy-enforced encryption.
http://www.mcafee.com/us/products/email-gateway.aspx
Emea
Emea
http://emea.trendmicro.com/emea/products/enterprise/email-encryption/gateway
Group IQ.Suite
Group technlogies ag - virus protection, security, and content filtering for lotus domino and exchange 2000 enterprise email systems
http://www.group-technologies.com/en/products/products/crypt.php
Symantec
Symantec universal gateway email is secure email communications without client software
http://www.symantec.com/business/universal-gateway-email
Trendmicro
Email encryption solution that fits your gateway -based encryption, client user-driven email encryption, and even a secure email hosted solution.
http://www.trendmicro.com/us/enterprise/network-web-messaging-security/email-encryption/index.html
SecurE-Mail Gateway
Secure-mail gateway is the intelligent solution for the automatic use of e-mail encryption and signature.
http://www.utimaco.com/c12570cf0030c00a/currentbaselink/w26k9k44363obelen