Category: Internet

Email

Helpful postfix Hints

On the servers I manage I use the postfix MTA (mail transfer agent). I occasionally find things about it that are not documented. I am adding this post to track those things so I can find them when need them. I hope some others can benefit from my notes. DKIM After setting up CWP (Control Web Panel) I found that users could not send email. It was being rejected due to a duplicate DKIM header. Literally the same, exact DKIM header appearing twice in the headers. CWP uses postfix with opendkim. Postfix was calling opendkim twice, both before and after...

July 28, 2022
DNS / Internet

Beware iDNS (and others)

Everything on the Internet has a numeric address, much like your phone number. The system that converts names (like pk1048.com) to numbers is called DNS or the Domain Name System and it is much like your phone’s address book. In order to use a name on the Internet you need to register that name. In the early days of the Internet there was only one name registrar, Network Solutions, and all names cost $35/year. Today there are many, many name registrars, of which Network Solutions is still one; others include GoDaddy and the one I use DynaDot. They all provide...

February 18, 2016
DNS / Geek / Internet

What Does PK1048 Mean

Geeks love inside jokes. Most (if not all) Unix commands actually have a meaning and are not just an assortment of random letters. So why did I choose PK1048 for my domain and blog? Well, back in the earlier days of the Internet (I do not claim to have been around for the real early days of the Internet in the 1960’s and 1970’s) you needed a way to manage domain names. These are the names we use to refer to things on the Internet, like coke.com, since all the Internet knows is the numeric address of the systems. The...

July 1, 2014
December 2024
M T W T F S S
 1
2345678
9101112131415
16171819202122
23242526272829
3031