In response to my entry on who holds problematic email , Evaryont left acomment lamenting the general 'don't trust the user's mail client'approach of mail submission servers accepting more or less everythingfrom clients and bouncing things later. This has prompted me to tryto think about the issues involved, so today you get this entry inreaction.

First, the basics. We already do our best to verify SMTP senderaddresses and immediately reject bad ones, for good reasons , and I hope that there'

When you design parts of a mail system, for example a SMTP submissionserver that users will send their email out through or your externalMX gateway for inbound email, you often face a choice of whetheryour systems should accept email aggressively or be conservativeand leave email in the hands of the sender. For example, on asubmission server should you accept email from users with destinationaddresses that you know are bad, or should you reject such addressesduring the SMTP conversation?

In theory, the SMTP RFCs combined with best

Mark Jason Dominus's Git remote branches and Git's missingterminology ( via )is about what it sounds like. This is an issue of some interest tome, since I flailed around in the same general terminology swampin a couple of recent entries . Dominus explains allof this nicely, with diagrams, and it helped reinforce things inmy mind (and reassure me that I more or less understood what wasgoing on).

He followed this up with Git's rejected push error , which covers a

Although it is now a little bit awkward to do this, let's startwith my tweet :

I see Twitter has broken viewing regular Tweets in a browser thatdoesn't run JavaScript (gives endless redirections to the mobilesite).

Twitter does this with a

The latest versions of uBlock Origin have added a new feature, the element zapper . To quote thedocumentation:

The purpose of the element zapper is to quickly deal with the removalof nuisance elements on a page without having to create one or morefilters.

uBlock Origin has always allowed you to permanently block pageelements, and a while back I started using it aggressively todeal with the annoyances of modern websites .This is fine and works nicely, but it takes work. I have to carefullypick out what I want

We have a small web app that uses Django (or is based on Django,depending on your perspective). As I write this, the latest versionof Django is 1.11.2, and the 1.11 series of releases started backin April. We're running Django 1.10.7 (I'm actually surprised we'rethat current) and we're probably going to keep on doing that fora while.

(Now that I'm looking at

Let's start with my tweet :

Do I want to know why a reported and disclosed in 2017 Linuxkernel vulnerability has a 2014 CVE number? Probably not.

Today, Ubuntu came out with USN-335-1 , a security advisory abouttheir Ubuntu 14.04 LTS kernel. Among the collection of CVEs fixedwas one that caught my eye, CVE-2014-9940 .This was simply because of the '20

Last year, I wrote about how your overall anti-spam system shouldhave manual emergency blocks . At the timeI was only thinking about incoming spam, but after some recentexperiences here, let me extend that and say that all entry pointsinto your overall mail system should have emergency manual blocks .This isn't just about spam or bad mail from the outside, or preventing outgoing spam , although those are importantthings. It's also because sometimes systems just freak out andexplode, and when this happens

I recently mentioned that I wasgoing to keep filtering aside email from the few mailing lists thatI'm subscribed to, instead of returning it to being routed straightinto my inbox. While I've kept to my decision, I've had to spendsome time fiddling around with just how I was implementing it inorder to get a system that works for me in practice.

What I did during my vacation (call it the vacation approach) wasto use procmail recipes to put each mailing list into a