It’s difficult, isn’t it? You’re being asked to get emails to the Inbox for the company so you can generate revenue but how can you be sure you’re doing the right thing? More to the point how do you know if you’re looked on as a good or a bad sender of emails? Our Email Reputation series will give some indication to you of the steps you can take to give yourself the best chance.

In Part 1 we’ll look at Sender Reputation generally, along with the basics of Masked Sending domains.


It’s a well known fact that around 85% of the world’s email traffic is SPAM (Talos Intelligence shows around 316 billion emails delivered daily that are SPAM and only 56 billion that are legitimate traffic). That’s not a good place to start from, because you know the ISPs out there are looking to block that spammy traffic, so let’s hope you’re not going to get flagged for no good reason.

With the ratio above of 56 to 316, it’s no wonder that it can be a hard time getting into the Inbox. However, it’s not a dark art, and it’s not rocket science. Here at Pure360 we work hard to fulfil our side of the obligation, by protecting ourselves from the many factors that play in this realm. We work with ISPs to deliver content where it is permitted and wanted, We work with Blacklist maintainers to understand what caused a particular listing and get it reversed, and not least we work with our clients to help them understand Best Practices and help them operate under those guidelines. You see, you get quite a bit for your money!

I mentioned best practices above, and how they play into your ability to deliver your emails and work on making revenue for your company from their investment in Email marketing. So, what can you do about that? Well let’s look at some of the variables here:

Sender Reputation

Pretty much every recipient of an email these days takes steps to ensure that a genuine sender is easily distinguishable from a less-than-reputable one.Typically this is done by the ISPs and/or Service Providers. They’ll have at least three layers to protect their recipients, which is usually further augmented by the individual recipient feeding back to the ISP or Service provider to give the individual’s response to an email (we’ll come back to that later).

Effectively you’re categorised by the First stage as one of three things:

  • A Good Sender – Your messages are well regarded and are very likely to land straight in the Inbox of the intended recipient. Obviously this is where you’d like to be every single time.
  • An Unknown sender – Messages you send may or may not arrive in the Inbox. Usually this is because you’ve not sent to these people before, but there may be other factors at play, such as having changed Email Service Provider (or ESP), your mail has come from an unexpected IP or other less obvious reasons.
  • A Bad Sender – You are limited in the number of emails that you send and that the recipient will accept. In all probability your email won’t even make it to the Inbox, but will be relegated to the Spam or Junk folder (assuming the Service Provider has given you the chance of getting that far in the first place).

The Mailbox provider has a vested interest in getting this right but quite often this can and will be to the detriment of the sender. However, there are a few factors that can help here.

Proper Masking

Whilst not every ESP out there uses the same methods for delivering an email in your name, one thing that is consistently needed across all of them are three records for the Internet to identify things as legitimate: SPF, DKIM and these days increasingly DMARC is a requirement. Although globally DMARC is not as well adopted as you might otherwise expect, if you want to get an email into a Public Sector Inbox in the UK, you are definitely going to need to have a DMARC record.  A detailed explanation exists here but in brief they work as follows:

  • SPF record – this is known as Sender Protection Framework and indicates to a recipient that the email came from an authorised IP address (or in other words a known and approved system on the internet). SPF lets the recipient’s Service Provider know that this computer has been authorised to send email on behalf of the Sender if the records in the header of the email that say where it came from match the records presented in the SPF record. For greater detail and a walk through of how this works see blog post here
  • DKIM record (or DomainKeys Identified Mail) – a security Key that has been embedded in the header of the email to say that the message is authorised and is this size in particular. Very useful because you can check to see if the message is exactly that size (i.e. has it been tampered with) and accept or reject on that basis. For greater detail and a walk through of how this works see blog post here
  • DMARC record (Domain-based Message Authentication, Reporting and Conformance) – This is a record that tells the recipient Service Provider how to handle the message it has just received based on the results of checking SPF and DKIM. It might look something like this:

Every ISP and Mailbox provider has their own filtering system that influences their delivery decision. Those cells highlighted in Grey above will be what happens to the email based on rules set out by the ISP. The ones shown are examples and not definitive by any stretch of the imagination.

Each and every ISP uses differing rules from the other, so do not rely on uniform behaviour here. Further, the ISP might change their mind if a large number of recipients start complaining about the message. For a few emails that fall in one of those grey boxes, you might be permitted a degree of license to deliver those messages. However, push it too far and the door will be most firmly slammed in your face for the duration of the campaign at least, and possibly longer.  You will almost certainly have been flagged at this point.

How detrimental that is largely depends on you at this point. Based on analysing your campaign data, you should be able to get a rough feel for what’s happened and then be able to adapt future campaigns accordingly.

That might mean that you have to slow deliveries to that ISP for a few campaigns. Don’t worry, we’ve got tools for that. You build a filter that allows you to segregate the recipients at that ISP, and you run two campaigns – one to that ISP (at a slower rate), and then send the second campaign to everyone else at the normal rate. Of course, you’ll want to check those campaigns to make sure you’re not running over the same speed bumps again. And you’ll want to talk to our experts about the results, just to make sure that you’re doing the right thing.

In Part 2 we’ll start looking at reputations and what we can do to keep them up.