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Category Archives: DKIM

Bolstering Email Authentication with ARC and Email Security with MTA-STS

In the most recent release of Cloudmark Security Platform (CSP) for Email 5.7, Cloudmark’s carrier-class email security gateway adds support for two emerging authentication and security protocol standards: Authenticated Received Chain (ARC, RFC 8617) and SMTP MTA Strict Transport Security (MTA-STS, RFC 8461). The ARC protocol addresses a difficulty in authenticating forwarded messages not addressed by other […]

Stopping Email Abuse in IPv6 Networks

Many service providers, network providers, and corporations plan to launch additional IPv6 networks and on-line services during this year’s World IPv6 Day, which falls on June 6th, 2012. IPv6 promises to enable deployment of a seemingly endless number of networks and devices.  IPv6 provides 128-bits of addressable space, while IPv4 only provides 32-bits.  This means […]

DKIM Helps and Hurts Google, YouTube and SalesForce

Google has been using DKIM to improve trust in mail it sends from several of its properties for some time now. Mail from Google staffers ( and, from YouTube (, from Google Groups ( and from Gmail users ( is always signed by DKIM using those respective domains as the signer. This means we […]

Highlights from IETF 82 in Taipei

The Internet Engineering Task Force met in Taipei in mid-November. Cloudmark was in attendance, working to advance several things through the IETF processes, including a new working group that will produce protocols and advice documents relevant to reputation services (see my previous posts about DKIM and domain reputation); creation of a working group seeking advancement […]

DKIM, New and Improved

After numerous discussions and spirited debate, the IETF has finally published a couple of important new RFCs related to DKIM. RFC6376 is the update to DKIM itself that does a thorough job cleaning up the original version, and RFC6377 provides recommended practices for using DKIM with respect to mailing lists. With this, DKIM has advanced […]

The value of domain names and email

The Internet Engineering Task Force (IETF) met last month in Prague.  Among the dozens of working groups striving to produce standards and guidelines to make the Internet work better, there is one called DKIM, or DomainKeys Identified Mail.  They’ve been working for several years to produce new email standards that can be added invisibly to […]

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