Ask the Silverpop Expert

Ask the Silverpop Expert

Which Internet service providers are still using some content filtering, and which are now completely reputation based?

The short answer is that most ISPs are utilizing both methods. As more major ISPs fully adopt the various authentication schemes, they are starting to track reputation based on these methods, as well as using the content filters they currently have in place.

Authentication, a process in which ISPs compare or verify the origin of messages as associated with the purported sender, can help identify legitimate senders from spammers. Seeking authentication is a good way to build up a positive reputation with ISPs. Currently, there are several authentication schemes:

  • Sender Policy Framework (SPF). Validates the domain and the “from” address against the machines that are authorized to send using that domain.
  • Sender ID. Compares the address of the server sending the mail with the pre-registered servers associated with that domain name.
  • DomainKeys Identified Mail (DKIM). Translates domain names (i.e. “”) into Internet Protocol (IP) addresses. Provides a means of associating a verifiable identity with a message. Given the presence of that identity, a receiver can make decisions about further handling of the message (e.g., delivery to inbox or rejection).

Additionally ISPs depend on their existing filters to rate traffic based on content, spam complaint rate, bounce rates, volume and email sent to spam traps. Some ISPs also base their judgments on a myriad of external (third-party) tools to track the performance of senders by both domain name and IP address. Every time you send from an IP address, your reputation goes up or goes down with each individual ISP, depending on a number of factors.

Therefore it’s important to avoid certain behaviors when looking to improve/maintain your reputation:

  • Drastically increasing the frequency of your sends compared to your regular, established pattern.
  • Introducing higher or irregular send volume patterns compared to your regular, established send volume.
  • Repeatedly sending to old, inactive email addresses.

In the end it is important for you to understand that everything you do as a marketer when sending email is being watched, weighted and scored and those measurements can affect, both positively and negatively, your reputation and the success of any future sends.