Simple steps: Avoiding the blacklists

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Messaging and Web security company MessageLabs earlier this month released its latest Intelligence Report for May 2007. The report showed an increase in sudden spam surges, often called spam spikes. In fact, the frequency of e-mailed viruses and phishing schemes increased even as spam rates decreased by 3.4%. (Although with 72.7% of all messages still being categorized as spam, that’s not saying much.)

In order to thwart this deluge of bad messages, companies and ISPs often turn to blacklisting to stop spam before it reaches their servers. Philip Thorne, CEO of e-mail marketing company Goolara, and Elie Ashery, CEO of e-mail marketing company Gold Lasso, said you can prevent blacklisting before it happens using simple techniques that all marketers should know about—but may not.

For example, one of the simplest ways to avoid getting blacklisted is by using throttling techniques, which keep you from over-saturating your prospects’ e-mail servers.

Throttling is exactly what it sounds like: managing the flow of e-mail going out of your servers and into another company’s. This is important, said Gold Lasso’s Ashery, because one of the ways a company can get placed on a blacklist is by sending too many e-mails from a particular IP address to particular servers.

Most corporate servers as well as ISPs set limits as to how many e-mails they will accept from an individual IP address within a set period of time, he said. “Once it crosses that threshold, the mail server starts blocking your IP address,” Ashery said.

Corporations and smaller ISPs may set that threshold between 1,000 and 10,000 messages within a 10-hour period, while larger ISPs might have much higher limits, such as 50,000 per day per IP, he said.

E-mail marketers can get around this limit by segmenting their lists manually or having their ESPs send out staggered groups of messages. “It’s a very big undertaking, but if you have a large list, you really need to do this one way or the other,” he said.

Of course, the other reason you might get on a blacklist is by having a large ratio of undeliverable-to-deliverable messages, said Goolara’s Thorne. When you send out an e-mail, you’re going to have some percentage of undeliverable messages. The problem comes, he said, when that happens too often or when an ISP receives too many undeliverables at once.

“Most ESPs use [e-mail server] engines that keep knocking on the door even once they have been returned the first time,” he said. “Even when the user is unknown or the content isn’t accepted. The ISP sees that they keep getting hammered with messages that look like spam so they blacklist you.”

Thorne suggested using an engine that lets you watch delivery in real time and react to it.

“You want to be able to see what the reaction is in real time and make adjustments,” he said. “If there’s a problem, such as a bad list or it seems like your content isn’t being accepted, you want to be able to stop it in real time.”

Not sure if your provider can do this for you? Just ask. “The providers have some ability to implement custom logic,” he said. “It’s something that everyone should be doing and will once people start talking and asking about it.”

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