I need IP addresses for reputation

Number one of seven in our occasional series on why ESPs need, or don’t need, lots of IP addresses to send mail properly.

I need at least one IP address per customer, to handle IP based reputation

Why this is right
While DKIM is gradually moving the main key for reputation tracking to a domain based token, right now the main key that is used to track reputation is the sending IP address.
If you have multiple customers sending mail of different quality using a different sending IP address for each of those customers means that the good customers will not be penalized by the poor behaviour of the bad customers. And, just as importantly, poor customers will not benefit from the behaviour of the good customers. This allows receivers to track sender reputation more accurately, and so delivery just wanted email to their recipients better. That makes everyone happy (other than the bad customers who deserve to be unhappy until they fix their practices).
Why this is wrong
Reputation is tied to sending IP address, but it’s also affected by volume of emails received from that IP address, and the consistency of volume. If a customer is only sending a few hundred emails a week to any given receiver ISP or they’re only mailing monthly then they won’t be able to maintain much of a positive reputation, simply because they’re too small to keep track of or because they mail so infrequently that each time they mail the receiving ISP will have forgotten about their previous mailings. In those cases the sender will be treated much the same as a new sender from a given IP address (neutral, at best, maybe poorly). For those cases a customer is likely to get better delivery rates if their mail is sent through an IP address pool that sends enough email overall to be noticed and tracked by receiving ISPs.
Another reason this is wrong
Reputation is tied to sending IP address, but receiving ISPs aren’t stupid and do recognize attempts to game the system. If you’re an ESP with a mix of good and bad customers then segregating the IP addresses they send from will not completely isolate the reputation of those customers from each other. The bad customers will drag your reputation as an ESP down more than the good customers will pull it up. And as your reputation as an ESP degrades it will pull down the reputation of your good customers much more than it will increase the reputation of your bad or unknown customers.
So segregating senders onto their own IP addresses doesn’t entirely separate their reputation from each other or from their ESP. And if you believe it does, you’re likely to make business decisions based on that misunderstanding that will badly affect your reputation and the delivery rates of your customers. Don’t fall into that trap.

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Technology does not trump policy when it comes to delivery

Recently Ken Magill wrote an article looking at how an ESP was attempting to sell him services based on the ESPs ‘high deliverability rates.’ I commented that Ken was right, and I still think he is.
Ken has a followup article today. In the first part he thanks Matt Blumberg from Return Path for posting a thoughtful blog post on the piece. Matt did have a very thoughtful article, pointing out that the vast majority of things affecting delivery are under the control of the list owner, not under the control of the ESP. As they are both right, I clearly agree with them. I’ve also posted about reputation and delivery regularly.

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Reputation as measured by the ISPs

Part 3 in an ongoing series on campaign stats and measurements. In this installment, I will look a little closer at what other people are measuring about your email and how that affects your reputation at the ISPs.
Part 1: Campaign Stats and Measurements
Part 2: Measuring Open Rate
Reputation at the ISPs is an overall measure of how responsive recipients are to your email. ISPs also look at how much valid email you are sending. Anything the ISP can measure and use to distinguish good mail from bad is used in calculating reputation.
Some of the major metrics ISPs use include the following.
Invalid Address Rates
The ISPs count how much mail from any particular IP address is hitting non-existent addresses. If you are mailing a large number of email addresses that do not exist (550 user unknown), this is a suggestion that your address collection techniques are not very good. Responsible mailers do have the occasional bad address, including typos, expired/abandoned addresses, but the percentage in comparison to the number of real email addresses is low. How low is low? Public numbers suggest problems start at 10% user unknowns, but conversations with ISP employees show they consider lower levels a hint there may be a problem.
To calculate bounce rate ISPs take the total number of addresses that were for invalid accounts and divide that by the total number of addresses that the sender attempted to send mail to. Rates above 10% may cause significant delivery issues on their own, rates lower that 10% may still contribute to poor delivery through poor reputation scores.
Spamtraps
ISPs pay a lot of attention to how much mail is hitting their “trap” or “bait” accounts. There are a number of different sources of these trap accounts: old abandoned email addresses, addresses that never existed or even role accounts. Hits to a trap account tells the ISP there are addresses on your list that did not opt-in to receive mail. And if there are some addresses they know about that did not opt-in, it is likely that there are other addresses that did not opt in.
Spamtraps tend to be treated as an absolute number, not as a percentage of emails. Even a single spamtrap on a list can significantly harm delivery. According to the ReturnPath Benchmark report lists with a single spamtrap had nearly 20% worse delivery than lists without spamtraps.
This is spam clicks (FBL complaints)
Complaints from users are heavily used by ISPs. This tells them directly how many people are objecting to your email. In this case, permission is removed from the equation. Even if a sender has permission to send email, the recipient can say “no, I don’t want this, it is spam.” The ISPs put more weight on what their users tell them than on what the senders tell them.

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Rescuing reputation

One of the more challenging things I do is work with companies who have poor reputations that they’re trying to repair. These companies have been getting by with poor practices for a while, but finally the daily delivery falls below their pain threshold and they decide they need to fix things.
That’s when they call me in, usually asking me if I can go to the ISPs and tell the ISPs that they’re not spammers, they’re doing everything right and will the ISP please stop unfairly blocking them. Usually I will agree to talk to the ISPs, if fixing the underlying problems doesn’t improve their delivery on its own. But before we can talk to the ISPs, we have to try to fix things and at least have some visible changes in behavior to take to them. Once they have externally visible changes, then we can ask the ISPs for a little slack.
With these clients there isn’t just one thing they’ve done to create their bad reputation. Often nothing they’re doing is really evil, it’s just a combination of sorta-bad practices that makes their overall reputation really bad. The struggle is fixing the reputation requires more than one change and no single change is going to necessarily make an immediate improvement on their reputation.
This is a struggle for the customer, because they have to start thinking about email differently. Things have to be done differently from how they’ve always been done. This is a struggle for me because I can’t guarantee if they do this one thing that it will have improved delivery. I can’t guarantee that any one thing will fix their delivery, because ISPs measure and weight dozens of things as part of their delivery making decisions. But what I can guarantee is that if they make the small improvements I recommend then their overall reputation and delivery will improve.
What small improvement have you made today?

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