Tagdns

Internet Storm Center on the Spamhaus DOS

The Internet Storm Center (ISC) has a blog post up discussing the DOS attack against Spamhaus. They do confirm they saw traffic approaching 300Gbps against Spamhaus. They also point out that most people probably never knew. The attack was significant, but not globally so despite the media reports to the contrary. When news of the attack reached the Internet Storm Center, we did have a brief...

More on the attack against Spamhaus and how you can help

While much of the attack against Spamhaus has been mitigated and their services and websites are currently up, the attack is still ongoing.  This is the biggest denial of service attack in history, with as much as 300 gigabits per second hitting Spamhaus servers and their upstream links. This traffic is so massive, that it’s actually affecting the Internet and web surfers in some parts of...

Troubleshooting tools

There have been a number of comments on my post about Hotmail moving to SPF authentication having to do with troubleshooting authentication failures. I have been helping clients troubleshoot these issues, and am able to take on new clients to solve authentication problems. Contact me for more information. Of course, many of these issues can be solved with access to the right tools. Steve’s...

MAAWG presents the first J.D. Falk award

Last week at MAAWG went much like all MAAWG conferences go: too much to do, too many interesting panels to attend, too many people to connect and work with, a plethora of very interesting keynote speakers and a total lack of sleep. Most of what happens at MAAWG is not public, but some of the events are. One of the things that I can talk about is the J.D. Falk award. This award was established by...

Setting up DNS for sending email

Email – and email filtering – makes a lot of use of DNS, and it’s fairly easy to miss something. Here are a few checklists to help: Data you need before you start: [table] Information,for example Return path / bounce address,bounces.myesp.com Mailserver hostname,mail4.myesp.com Mailserver external address,192.0.2.4 DKIM “d=”,greatbigmarketer.com DKIM selector,oct2012...

So you want to start a company? (part 4)

You’re setting up a company (or a new division or maybe even a new brand) and you’d like to use email to communicate with your customers. In this series of posts I’m going to touch on some of the things you can do today to make email life easier for you in the future. Today’s final post is on DNS hosting and setup. 5. DNS hosting DNS is what lets you actually use the domain you’ve...

The view from a blacklist operator

We run top-level DNS servers for several blacklists including the CBL, the blacklist of infected machines that the SpamHaus XBL is based on. We don’t run the CBL blacklist itself (so we aren’t the right people to contact about a CBL listing) we just run some of the DNS servers – but that means that we do get to see how many different ways people mess up their spam filter...

Basic email delivery using telnet

Whenever we’re working with someone to diagnose some obscure delivery issue one of the things we usually have them try is to “run a transaction by hand”. Being able to do that is a trick that everyone working with email should be able to do. I was drafting a blog post today and wanted to refer to running a transaction by hand and I realized that we hadn’t actually...

Troubleshooting the simple stuff

I was talking with one of my Barry pals recently and was treated to a rant regarding deliverability experts that can’t manage simple things. We’ve been having an ongoing conversation recently about the utterly stupid and annoying questions some senders ask. Last week, I was ranting about a delivery person asking what “5.7.1. Too many receipts this session” meant. This...

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