Blocklist BCP

As many of you may be aware there is a draft document working its way through the Internet Research Task Force (IRTF) discussing best common practices for blocklists. The IRTF is a parallel organization to the IETF and is charged with long term research related to the Internet. The Anti-Spam Working Group was chartered to investigate tools and techniques for dealing with spam.
Recently the ASRG posted a draft of a best practices document aimed at those running blocklists (draft-irtf-asrg-bcp-blacklists-07). This document has been under development for many years. The authors have used this document to share their experiences with running blocklists and their knowledge of what works and what doesn’t.
Best practices documents are never easy to write and consensus can be difficult. But I think that the authors did a good job capturing what the best practices are for blocklists. I do support the document in principle and, in fact, support many of the specific statements and practices outlined there. As with any best practices documents it’s not perfect but overall it reflects the current best practices for blocklists.
Ken Magill’s article about the BCP
Anti-Abuse buzz article about the BCP

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GFI/SORBS considered harmful, part 3

Act 1 • Act 2 • Intermezzo • Act 3 • Act 4 • Act 5
Management Summary, Redistributable Documents and Links
In the last few days we’ve talked about GFI’s lack of responsiveness, the poor quality of their reputation and blacklist data, and the interesting details of their DDoS claims. Today we’re going to look at (some of) the fundamental problems with GFI’s procedures and infrastructure that cause those issues. Some of the subset of issues I’ve chosen highlight are minor, some are major, but they show a pattern of poor decisions.
SSL Certificates
When you use SSL on a web connection it brings you two benefits. The first is that it encrypts the connection between your browser and the webserver, so that it’s very difficult for anyone to watch or tamper with your interaction with that webserver. The second, more important, reason is to make sure that you’re talking to the webserver you think you’re talking to, to avoid man-in-the-middle attacks.
This security relies on you trusting the certification authority that issues the SSL certificate that the website uses. A website providing services to the public should always use an SSL certificate created by one of a small number of reputable certification authorities that are pre-loaded into all webservers as “trusted”. These SSL certificates are something that need to be be purchased, but they’re very inexpensive – less than ten dollars a year.

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Content based filtering

A spam filter looks at many things when it’s deciding whether or not to deliver a message to the recipients inbox, usually divided into two broad categories – the behaviour of the sender and the content of the message.
When we talk about sender behaviour we’ll often dive headfirst into the technical details of how that’s monitored and tracked – history of mail from the same IP address, SPF records, good reverse DNS, send rates and ramping, polite SMTP level behaviour, DKIM and domain-based reputation and so on. If all of those are OK and the mail still doesn’t get delivered then you might throw up your hands, fall back on “it’s content-based filtering” and not leave it at that.
There’s just as much detail and scope for diagnosis in content-based filtering, though, it’s just a bit more complex, so some delivery folks tend to gloss over it. If you’re sending mail that people want to receive, you’re sure you’re sending the mail technically correctly and you have a decent reputation as a sender then it’s time to look at the content.
You want your mail to look just like wanted mail from reputable, competent senders and to look different to unwanted mail, viruses, phishing emails, botnet spoor and so on. And not just to mechanical spam filters – if a postmaster looks at your email, you want it to look clean, honest and competently put together to them too.
Some of the distinctive content differences between wanted and unwanted email are due to the content as written by the sender, some of them are due to senders of unwanted email trying to hide their identity or their content, but many of them are due to the different quality software used to send each sort of mail. Mail clients used by individuals, and content composition software used by high quality ESPs tends to be well written and complies with both the email and MIME RFCs, and the unwritten best common practices for email composition. The software used by spammers, botnets, viruses and low quality ESPs tends not to do so well.
Here’s a (partial) list of some of the things to consider:

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It's not illegal to block mail

My post “We’re going to party like it’s 1996” is still getting a lot of comments from people. Based on the comments, either people aren’t reading or my premise wasn’t clear.
Back in 1996 the first lawsuits were brought against ISPs to stop ISPs from blocking email. These suits were failures. Since that time, other senders have attempted to sue ISPs and lost. Laws have been written protecting the rights of the ISPs to block content they deem to be harmful.
Dela says that he was just attempting to open up a conversation, but I don’t see what he thinks the  conversation is. That ISPs shouldn’t block mail their customers want? Sure, OK. We’re agreed on that. Now, define what mail recipients want. I want what mail I want, not what someone else decides I might want.
Marketers need to get over the belief that they own end users mailboxes and that they have some right to send mail to people. You don’t.
When marketers actually start sending wanted mail, to people who actually subscribe – not just make a purchase, or register online or happen to have an easily discoverable email address – then perhaps marketers will have some standing to claim they are being treated illegally. Until and unless that happens, the ISPs are well within their rights to block mail that their users don’t want.

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