Reputation and "the cloud"

As Reddit recently learned it’s not a great idea to use the Amazon EC2 cloud to host mailservers. There are a number of reasons for this, most of them related to the reputation of mail coming from EC2 servers.
When you’re using machines in the cloud, changing IP addresses is as simple as initializing a new server. Spammers discovered this almost as soon as the EC2 cloud became public. They would set up a mailserver and send spam through that server until it was blocked. Then they’d just start another instance to avoid the block and keep spamming. They had an almost unlimited number of IP addresses to abuse and moving around was easy to do. Amazon did little to stop the spam coming from the cloud so many ISPs and spam filtering companies blocked email from the entire range of IP addresses allocated to the EC2 cloud.
Blocking large swathes of network space that are consistent sources of abuse is well accepted as a method of dealing with spam. Yes, this form of blocking has inconvenienced legitimate companies who aren’t actually doing anything wrong. But when a service provider doesn’t take sufficient action to stop customers from spamming through their networks, then ISPs will implement countermeasures.

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What makes a good ESP?

There are a number of things that make a responsible ESP, including setting and enforcing standards higher than those set by the ISPs.
One of the responsible ESPs is Mailchimp. (Full disclaimer, I do consult for Mailchimp.) This ESP focuses on businesses with small to medium sized lists. They screen new customers for source of permission as well as mail content.
As well as putting a human in the loop and identifying problem customers manually, they have also developed an automated process that predicts the likelihood that a certain customer will violate their standards. This process is very similar to the reputation process in place at many ISPs. Customers that are flagged as potential problems are reviewed by staff members who contact the customer for further clarification.
What’s the benefit of this process? A good reputation, a clean customer base and positive notice by the ISPs. In fact,  just recently I was contacted by one of the very large consumer ISPs, confirming that Mailchimp is one of my clients. He informed me that he’d noticed a few of the Mailchimp IPs had a really high reputation but weren’t whitelisted. He asked me to send him all of their IPs so he could make sure all their IPs were whitelisted.
Proactive auditing of customers and predictive modeling of mailing results is working for Mailchimp and their customers.
Some ESPs have aggressive cancellation policies, which helps them police their networks and their customers. I often encounter former customers of these ESPs, either as direct clients or as customers of my ESP clients. In one case, I was asking around about a new client at their old ESP. “They tell me they left you under their own power and there was no spam issue involved, can you comment?” The policy person would not comment specifically about that client, but did comment that “95% of our former customers were disconnected for cause.”
These are two examples of ESPs that are working hard to minimize the amount of unwanted mail going through their network. They have invested time and energy into tools and staff to monitor the network. Staff is empowered to make decisions about customers and management believes no customer is “to big to disconnect.”
Tomorrow we’ll look at typical ESPs and their normal practices.

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Reddit and email

Ben over at Mailchimp writes about Reddit discovering a lot of their mail was being blocked because they were sending from the Amazon EC2 cloud.

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Reputation

It used to be that every potential client that called me up to ask me to help them with their delivery issues would tell me they weren’t a spammer. Over the last year or so that’s changed to telling me that they have a good reputation and don’t understand why they’re having delivery problems.
This leads me to believe that there is some confusion about what reputation is and what reputation is not.
Reputation is a shorthand term for a complex formula measuring the history of email from an IP address. Some reputation schemes measure the history of email containing a particular URL or domain.
Recipient domains measure a lot of things and use them at various points during the email transaction. Some measurements are integrated into a single value that is queried during the SMTP transaction. If the measurement is too bad, the email is rejected or rate limited. Other measurements are queried after the email is accepted by the ISP, and those values determine if an email is delivered to the inbox or the bulk folder.
There are a couple important things to remember about reputation.

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