How to burn an ISO image with OS X El Capitan

Sometimes it’s important that things change for no apparent reason. You know, the way they move things around in supermarkets just to drive you crazy. If you’ve tried burning an ISO image to disk in El Capitan recently, you know what I’m talking about: because the option to burn an ISO has been removed from … Read more

How to remove an IP from the CBL (Composite Blocking List)

Today I was introduced to something called the CBL, or the Composite Blocking List. This is one of several Spamhaus projects that’s there to make sure IP’s are blacklisted when they’re sending spam.

You can check if your IP’s are OK at

The CBL is a separate website in which you can also lookup IPs. Spamhaus will tell you if that’s the case and direct you to the CBL here:

Even though my IP was otherwise fine, it was listed in the CBL, and Yahoo kindly made me aware of this as part of an error message I’ve received when trying to send an email. If ever there is an email problem in CentOS, the first place to look is /var/log/maillog. Here’s Yahoo’s very helpful explanation:

Turns out that the hostname was not setup yet, so the box would respond as localhost.localdomain. That’s a big fat no-no as far as the CBL people are concerned. Here’s CBL’s explanation:

This IP address is HELO’ing as “localhost.localdomain” which violates the relevant standards (specifically: RFC5321).

The CBL does not list for RFC violations per-se. This _particular_ behaviour, however, correlates strongly to spambot infections. In other words, out of thousands upon thousands of IP addresses HELO’ing this way, all but a handful are infected and spewing junk. Even if it isn’t an infection, it’s a misconfiguration that should be fixed, because many spam filtering mechanisms operate with the same rules, and it’s best to fix it regardless of whether the CBL notices it or not.

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How to set the hostname on CentOS and Fedora

CentOS 7 has a nice command called hostnamectl. With it we can display the current hostname, and set any of the three types of hostname: static hostname (something like transient hostname (anything you like, assigned when using DHCP) pretty hostname (something like Jay’s MacBook Pro) By default, a CentOS installation comes back with localhost.localdomain … Read more

How to avoid hyphenations in TwentyFifteen by Automattic

By default, TwentyFifteen will hyphenate text on posts and pages. This works well for most, but some find this feature annoying. It’s easy to override with a small CSS tweak – let me show you how. Here’s what a post might look like by default: Notice the hyphenations in lines 3 and 4. Now add … Read more