Geekblok

BOK surprised me with an invitation email about a website I never noticed. The small mail suggested that I should check it out and maybe write a little about it here, due to absence of BOK this weekend.

So I did check it out and had no clue what to expect. The sign up was easy enough and after a few seconds, I was looking at my online “notebook” hosted by Evernote.

I’ve seen such dump sites before and they never really seemed to interest me for more than a minute. I know Joffie has his own wiki at home for dumping notes, and I have CVS and SVN software installed on my home machine(s) so I don’t really need this either. But then I found out it also offers text recognition within images. Now that’s something my `grep` can’t do, so this might be nice! Time to explore the service after all.

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Email address validation can be rather tricky. RFC822 gives you some pointers, but to validate an address is still pretty darn hard. In Perl, there’s the module Email::Valid to help you, which does a rather good job, but look at the source for the regexp!

Today I came across a new website called spam-proof-email-generator. Of course I threw in a query that’s bugging quite a lot of parsers: my+address@mailserver.somedomain.co.uk. Most of such JavaScript “checks” hang on the plus sign (which is perfectly valid, and quite useful!) and the subdomain part. And yep, this website tells me the address in invalid. Strange, for you’d expect a site designed for handling email addresses to be a bit more careful!

So let’s look at their technique. Their validation is merely done on the client side (JavaScript). The code is childishly simplistic though. This regexp will determine whether your address is valid or not (broken down into two lines): /^[a-zA-Z][\w\_\.-]*[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]* [a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$/;

But when you disable JavaScript, you can bypass this simple check and insert any string you like, as you can see here:

So, yeah, rather a useless service. Why not create your own image with GIMP/Photoshop, use JavaScript to display the address or use something like user [at] domain [dot] com?

Today I received one of those emails again:

Subject: **Message you sent blocked by our bulk email filter**<br /> Body: Your message to: &lt;h.bokking@some-domain.dom&gt;<br /> was blocked by our Spam Firewall.<br /> The email you sent with the following subject has NOT BEEN DELIVERED:<br /> Subject: October 70% OFF

Well… thanks but no thanks, postmaster at edutel.nl!

I can very well understand the message was denied by their “Barracuda Spam Firewall” : the message originated from Russia and the V-pills-word was included in the “From”-header, two reasons enough to mark a message as spam. But I was never the actual sender of that message, since the “From” was forged…

This is a common technique used by spammers, but to overcome this one should never ever BOUNCE spam!! There’s even a whole page dedicated to “Why you shouldn’t bounce spam and viruses“, explaining why it’s better to REJECT these kind of emails. A must-read for every so called postmaster!

I myself don’t reject, but DISCARD all spam-messages identified by SpamAssassin / amavisd-new into a separate folder for further analysis, so it gives me the opportunity to make some tweaks to the spam-filter itself.

Many people face the problem of handling e-mails efficiently. There is no right or wrong way to handle e-mail, but some methods just are a little easier to work with than others.

A lot of people ask me how I handle all my e-mails. In this post I’ll describe my setup. It’s far from perfect, but for me it works and it might work for you too.

I’m a Linux geek, so I use a CLI mail agent, named mutt. This simple yet powerful piece of software is wisely described as:

All mail clients suck. This one just sucks less.

As funny as it might sound, it’s true. After using PINE for a long time, I’ve switched to mutt and never looked back. The interface is powerful and it does close to everything you’d want your mail client to do. Other things, like filtering the mail, I do with a custom script using Mail::Audit (yes, I should use Email::Filter). I prefer a custom Perl script over procmail for I have difficulty grasping the procmail way of writing filters and rules. It just seems too complicated to me. Mail::Audit is a lot more simple, as we’ll see in a minute.

Ok, now that we know the tools we’re working with, let’s look at how I hook it all up.

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