I was recently involved in a discussion about what matters more, Sender Score or DKIM signing?
As an ISP email engineer that provides SMTP relay service for email sent by others, my primary focus is protecting the Sender Scores of those SMTP relays, for example:
A growing number of customers have SPF records. A few have implemented DKIM / DomainKeys.
It is my experience, based on what typically helps get customer tickets resolved, that SPF and DKIM help get email delivered to the inbox vs. the spam folder, but they don't play a major role in bypassing reputation checks that determine a sender has a low sender score. A high sender score is required to even consider getting an email looked at, and the the SPF & DKIM are some of the factors that can help with not getting filtered to the spam folder.
I'm expecting that other factors matter more such as long term positive interactions such as are their recipients at large email services replying to and clicking links in the email?
A broken or misconfigured SPF and/or DKIM record can override a great sender score and cause deliverability issues.
My ranking of what seems to matter the most can be found from top to bottom in this recent post:
Gmail delivers email from my exchange server to the spam folder | Email Questions
The next example I'd like to discuss is the owner of a VPS with a fairly big forum who recently changed IP addresses:
The specific high impact metric impacting that score is "sender rejected"
The IP has a PTR that appears dynamic and not statically assigned to a mail server.
It was reported that the forum has issues with being marked as spam before the IP address change.
Without knowing the specifics of the email being sent I'd recommend checking the following:
In this case, if nothing else improves, how much could creating an SPF record and DKIM signing outgoing email help the forum owner to get their emails accepted and delivered to the inbox?
How does that answer change as more email services implement DMARC on their incoming mail servers?
Keep in mind this type of sender is probably not trying to help get bad email blocked so much as trying to get what is supposed to be good email accepted.
Should we expect at least a small shift away from the importance of Sender Score?
The last case I'd like to bring up is that of the sender with no sender score:
There are senders in this category that believe creating SPF records and DKIM signing play a HUGE role in helping email service providers determine what to do with their email.
What is the actual impact these improvements should make on getting email accepted and inbox delivered?
I suspect no sender score is better than a score below 60, and that it varies by provider how suspicious they treat the email.
A sender in this category stated an improvement from email rejected to email accepted by Hotmail.
It's unknown to me if that meant accepted but delivered to the Junk folder.
I don't think any of the senders in the 55 or insufficient group know if they're going mostly to the Inbox or Junk and that they are relying on member feedback to find out if/when there are problems.
All that said, I'm left wondering which matters more, DKIM signing or Sender Score?
My take is that Sender Score gets you in the door and SPF/DKIM help get you to the inbox.
As an ISP email engineer that provides SMTP relay service for email sent by others, my primary focus is protecting the Sender Scores of those SMTP relays, for example:
A growing number of customers have SPF records. A few have implemented DKIM / DomainKeys.
It is my experience, based on what typically helps get customer tickets resolved, that SPF and DKIM help get email delivered to the inbox vs. the spam folder, but they don't play a major role in bypassing reputation checks that determine a sender has a low sender score. A high sender score is required to even consider getting an email looked at, and the the SPF & DKIM are some of the factors that can help with not getting filtered to the spam folder.
I'm expecting that other factors matter more such as long term positive interactions such as are their recipients at large email services replying to and clicking links in the email?
A broken or misconfigured SPF and/or DKIM record can override a great sender score and cause deliverability issues.
My ranking of what seems to matter the most can be found from top to bottom in this recent post:
Gmail delivers email from my exchange server to the spam folder | Email Questions
The next example I'd like to discuss is the owner of a VPS with a fairly big forum who recently changed IP addresses:
The specific high impact metric impacting that score is "sender rejected"
The IP has a PTR that appears dynamic and not statically assigned to a mail server.
It was reported that the forum has issues with being marked as spam before the IP address change.
Without knowing the specifics of the email being sent I'd recommend checking the following:
- Check the outgoing mail logs for any signs of a compromised plugin sending spam
- Are too many registration confirmation emails being sent to spammers?
- Is there a plugin sending "forum newsletters" to email addresses that didn't subscribe?
- Are there other web sites on the same server that could be causing the score to stay low?
- Are members with email addresses that bounce getting their thread subscriptions removed?
- Is the IP on any blacklists related to a previous account at the hosting company?
In this case, if nothing else improves, how much could creating an SPF record and DKIM signing outgoing email help the forum owner to get their emails accepted and delivered to the inbox?
How does that answer change as more email services implement DMARC on their incoming mail servers?
Keep in mind this type of sender is probably not trying to help get bad email blocked so much as trying to get what is supposed to be good email accepted.
Should we expect at least a small shift away from the importance of Sender Score?
The last case I'd like to bring up is that of the sender with no sender score:
There are senders in this category that believe creating SPF records and DKIM signing play a HUGE role in helping email service providers determine what to do with their email.
What is the actual impact these improvements should make on getting email accepted and inbox delivered?
I suspect no sender score is better than a score below 60, and that it varies by provider how suspicious they treat the email.
A sender in this category stated an improvement from email rejected to email accepted by Hotmail.
It's unknown to me if that meant accepted but delivered to the Junk folder.
I don't think any of the senders in the 55 or insufficient group know if they're going mostly to the Inbox or Junk and that they are relying on member feedback to find out if/when there are problems.
All that said, I'm left wondering which matters more, DKIM signing or Sender Score?
My take is that Sender Score gets you in the door and SPF/DKIM help get you to the inbox.
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