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Ken Simpson

126 posts

Industry

Why Did AOL Send Me “554 (RTR:BL) http://postmaster.info.aol.com/errors/554rtrbl.html”?

October 2, 20122 min read

We discuss why AOL’s mail servers sometimes respond with the error message “554 (RTR:BL)” and what you can do to get email flowing to AOL users.

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Industry

How Botnets Send Spam (In Layman’s Terms)

October 1, 20123 min read

A guest blogger describes how and why spammers use bot nets to send spam.

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Industry

What is fakemx.net and why are they temp failing me?

September 26, 20121 min read

In this post, we discuss what fakemx.net is, and why it’s generating temporary delivery failure notices in your mail server logs.

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Industry

Why Is Yahoo! Temp Failing My Mail?

September 25, 20122 min read

We explain why Yahoo! fails connections to its mail servers with error: 421 4.7.0 [TS01] Messages from 1.2.3.4 temporarily deferred due to user complaints.

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Industry

Most popular SMTP responses – updated for August 2012

August 31, 20123 min read

A summary of the top-50 most popular SMTP error responses, as collected at a major web hosting provider.

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Industry

How did I get 412,139 spam messages in my Gmail spam box?

July 5, 20121 min read

How did I get 412,139 spam messages in my Gmail spam box?

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Industry

The leap second that killed the Internet (well, parts of it)

July 3, 20121 min read

A bug in various software components caused a severe global outage of various services including the popular social news site Reddit.

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Industry

LinkedIn Password Leak: Probably Not Brute Forced

June 7, 20122 min read

Someone recently stole 6.5 million passwords from LinkedIn, publishing a list of SHA1 password hashes. We explain why we think these weren’t brute forced.

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