A sledge hammer introduction to X.509 certificates

Introduction First and foremost: Crypto is not my expertise. This is a note to future self for the next time I’ll need to deal with similar topics. This post summarizes my understanding as I prepared worked on a timestamp server, and it shows the certificates used by it. There are many guides to X.509 certificates [...]

Apache 2.4: RewriteRule with [NE] causing 500 Internal Server Error

This is the weirdest thing. With an Apache 2.4.10 on Linux Debian 8 (yes, old), and a relatively simple mod_rewrite rule in .htaccess going RewriteCond %{HTTP_HOST} !^www\. [NC] RewriteRule (.*) https://www.mysite.com/$1 [R=301,L,NE] This is really nothing special. Just pushing users to the www host name, if they were lazy typing it. This works almost perfectly, [...]

How to edit login passwords in Google Chrome

Introduction Unlike Firefox, Google Chrome doesn’t allow editing passwords (at least not the version I have, and it seems like this feature will be added). One possible workaround is to enable Google Sync for passwords, and have those stored on the server: It’s possible to edit the passwords at passwords.google.com. If you have no problem [...]

Firefox: Stop that nagging on available updates

After upgrading to Firefox 72.0.1 on Linux, I got a tab encouraging me to upgrade Firefox (and that it couldn’t be done automatically). To make things worse, the option to turn off automatic upgrades checks has been removed from the GUI interface. Why? Call it what you want, at the bottom there’s a “let’s force [...]

A VoIP phone at home: The tech details on leaving your phone company

Introduction This is some information and hard-learned wisdom I collected while setting up an Israeli phone number for use with a VoIP phone, so I can accept calls with a regular Israeli phone number and also make outbound calls. Important to note is that I did this without the local ISPs that provide this service. [...]

MySQL, OOM killer, overcommitting and other memory related issues

It started with an error message This post is a bit of a coredump of myself attempting to resolve a sudden web server failure. And even more important, understand why it happened (check on that) and try avoiding it from happening in the future (not as lucky there). I’ve noticed that there are many threads [...]

AudioCodes MP202B hacking notes (Netvision)

This is a no-go These are notes during my failed attempts to turn an old (2011?) Israeli ISP provider’s SIP adapter (MP202B, provided by Netvision) into one that works with any SIP provider. The first step is to get access of its configuration, and that’s exactly where it stopped. Netvision has taken action to prevent [...]

Add-on icons vanished after Firefox upgrade

Don’t get me wrong: I didn’t upgrade Firefox. It upgraded itself suddenly into Firefox 68.o Quantum. How did I notice? Not because it became any better, but because suddenly things stopped working. And I got logged out from several sites. For example, my Adblocker and other add-on suddenly vanished. Checking the add-on settings, the relevant [...]

Setting up your own authoritative DNS server jots

What’s this? These are somewhat random jots I made while setting up an authoritative BIND server, so that a simple VPS machine can function standalone. Well, almost standalone, as it takes some help from a slave DNS to supply the second DNS entry. But even if that slave goes away suddenly, the show will go [...]

The art of setting up a sendmail server on Debian 8

But why? Fact number one: Running your own mail server is the most likely cause for messing up, and that can mean an intrusion to the server or just turning it into a public toilet for spam. Nevertheless, if mail delivery is important to you, there’s probably no way around. And I’m not talking about [...]