Email Deliverability

Posted by on Oct 30, 2009 in Email Marketing | Comments Off on Email Deliverability

I originally included information on email deliverability in my eCards post, but thought it is such an important topic, that it deserves its own post.

Most likely when sending bulk emails you will be working with an Email Service Provider (ESP) or email house. When selecting an ESP and getting set up to send newsletters, announcements, press releases, eCards, or any bulk mailings, the most critical criteria is the ESP’s deliverability.

The factors to consider are listed below.

Email Authentication
Over 90% of email marketers authenticate emails that are sent.

  • Reverse DNS enabled mail server
    Reverse DNS allows a receiving mail server to go back to the authoritative DNS servers for a domain and verify that the host trying to send mail actually exists at that domain and with the IP address claimed by the sender. If your ISP will delegate reverse DNS lookup to your servers, you can handle it yourself. If not, you will need to give your ISP the information necessary so it can create the reverse DNS zone on its servers. You can see your current reverse DNS information at
  • DomainKeys/DKIM (a TXT record in the DNS settings )
    DomainKeys is an email authenication system designed to verify the DNS domain of an email sender and the message integrity. The DKIM publishes a public key in the domain’s DNS that receivers use to validate your DKIM signed messages.
  • SPF Authentication
    The Sender Policy Framework (SPF) allows the owner of a domain to specify their mail sending policy, e.g. which mail servers they use to send mail from their domain. That is, the SPF record lists all email servers that are authorized to send email on behalf of your domain. The technology requires two sides to play together: (1) the domain owner publishes this information in an SPF record in the domain’s DNS zone, and when someone else’s mail server receives a message claiming to come from that domain, then (2) the receiving server can check whether the message complies with the domain’s stated policy. If, e.g., the message comes from an unknown server, it can be considered a fake.
  • Compliance with current SMTP RFC standards

Sender Reputation
Your reputation and your ESP’s reputation are very important assets and should be carefully protected.

  • Will your emails go out through a dedicated IP?
    You don’t want bad behavior of other clients to impact the deliverability of your emails.
  • Mailer server configuration set to “Open relay off”
    A well-configured mail server should NOT relay third-party email. Otherwise, the server is subject to abuse by vandals and spammers, and probable blacklisting by recipients of the unwanted third-party e-mail. For information on how to secure a mail server against third-party relay, visit

  • Track and honor all opt-out requests

  • Continuously cleanse email lists.
    You want as few hard bounces as possible.
    With all of the recent staff changes at companies, keeping active email addresses current is an ongoing activity. Put processes and procedures in place to make sure the CRM content data is consistently kept current.

  • Monitoring E-mail server log files for failed deliveries to determine if there are any domains rejecting e-mail from the company domain. Know what your ESP’s processes and procedures are for monitoring Email Block Lists. You can also check to see if your Domain, or your ESP’s Domain IP address is listed on SpamCop or SpamHaus (a registry of known spam operations).

Additional ESP Services
To measure the impact of your email campaigns, you will want access to reports on each mailing.

  • Reports on soft and hard bounces
  • Management of opt-outs
  • “Spam Check” Feature that lets you test the email before sending it out to see if contains info that may appear as spam. For example, do they use something like SpamAssassin engine to “score” an e-mail for spam content.
  • Reports on the email deliveries, opens, click through 

Email Houses
Some of the more reputable email distributors include:

  • Benchmark Email
  • Bluehornet
  • Bronto Software
  • Campaigner
  • Constant Contact
  • Exact Target
  • JangoMail
  • Puresend
  • Silverpop
  • iContact
  • MailChimp
  • VerticalResponse

Jean Steckler
Steckler eMarketing
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