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.

Godzilla sneaks up on Tokyo
Godzilla sneaks up on Tokyo

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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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Confirmed opt-in

I spent the morning in multiple venues correcting mis-understandings of confirmed opt-in. The misunderstandings weren’t so much that people didn’t understand how COI works, but more they didn’t understand all the implications.
In one venue, the conversation centered around how small a portion of deliverability the initial subscription process affects. Sure, sending unwanted, unexpected email can and does cause reputation problems, but merely using COI as a subscription methodolgy doesn’t automatically give a sender a good reputation or good delivery. Senders using COI as a subscription practice need to also need to send relevant and engaging mail that their recipients expect to receive. They need to handle their bounces well and purge or re-engage inactive subscribers. They need to keep their complaints low and their responses high.
How you manage subscriptions is only one factor in reputation schemes, and even if the subscription method is COI other factors can negate any bonus involved.
The second conversation involved Ken challenging me on the comment I left on his quiz yesterday. I said COI wasn’t foolproof and he challenged me to explain how. I did, and he’ll be following up next week.

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Winning friends and removing blocks

I do a lot of negotiating with blocklists and ISPs on behalf of my clients and recently was dealing with two incidents. What made this so interesting to me was how differently the clients approached the negotiations.
In one case, a client had a spammer slip onto their system. As a result the client was added to the SBL. The client disconnected the customer, got their IP delisted from the SBL and all was good until the spammer managed to sweet talk the new abuse rep into turning his account back on. Predictably, he started spamming again and the SBL relisted the IP.
My client contacted me and asked me to intercede with Spamhaus. I received a detailed analysis of what happened, how it happened and how they were addressing the issue to prevent it happening in the future. I relayed the info to Spamhaus, the block was lifted and things are all back to normal.
Contrast that with another client dealing with widespread blocking due to a reputation problem. Their approach was to ask the blocking entity which clients they needed to disconnect in order to fix the problem. When the blocking entity responded, the customer disconnected the clients and considered the issue closed. They didn’t look at the underlying issues that caused the reputation problems, nor did they look at how they could prevent this in the future. They didn’t evaluate the customers they disconnected to identify where their processes failed.
The first client took responsibility for their problems, looked at the issues and resolved things without relying on Spamhaus to tell them how to fix things. Even though they had a problem, and is statistically going to have the occasional problem in the future, this interaction was very positive for them. Their reputation with the Spamhaus volunteers is improved because of their actions.
The second client didn’t do any of that. And the people they were dealing with at the blocking entity know it. Their reputation with the people behind the blocking entity was not improved by their actions.
These two clients are quite representative of what I’ve seen over the years. Some senders see blocking as a sign that somehow, somewhere there is a flaw in their process and a sign they need to figure out how to fix it. Others see blocking as an inconvenience. Their only involvement is finding out the minimum they need to do to get unblocked, doing it and then returning to business as usual. Unsurprisingly, the first type of client has a much better delivery rate than the second.

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