Take a look at some forums for large broadband internet providers, and you'll see users complaining that they are unable to send emails addressed at Hotmail or MSN. It takes a good observer however to notice the problems, because the email doesn't bounce. Instead it will simply vanish as if it never existed.

Microsoft too is puzzled by this issue. They were notified about a forum where Apple  ranted about the problem on Tuesday. They have been investigating the problem ever since, but refuse to provide any background about what is going on.

The Hotmail outage doesn't just affect Apple users. Subscribers of Comcast, Rogers and Cogeco (all broadband internet providers) too have reported problems with sending email to Hotmail and MSN.

When presented with these problems, email security experts all have the same conclusion: spam filters gone bad.

In these days of botnets, broadband providers are the number one sources of spam email messages – one source told vnunet.com that Comcast is notoriously bad in curbing spam originating from its network. So the likely cause here is that whenever Hotmail gets fed up with one provider, they tweak their servers and make it harder for that one provider to reach them. This will then cause the provider to investigate what's going on and ideally have them call Microsoft – but in some cases (like Comcast's) they take more drastic measures and just shut down their servers.

"These things almost become like a comedy of errors," Andrew Lochart, director of product marketing for email security vendor Postini told vnunet.com.

It might be funny to Mircrosoft and the providers, but as usual the users are caught in between.

Tags: Microsoft, hotmail, spam, botnet, Comcast, rogers, cogeco

28 Oct 2005