For reasons beyond the scope of this entry, I've been building aVPN server that will support WireGuard (along with OpenVPN and L2TP). A server needs a client, so I spentpart of today setting up my work laptop as a WireGuard client in a 'VPN' configuration, under NetworkManagerbecause that's what my laptop uses. I was hoping to do this throughthe Cinnamon GUIs for NetworkManager, but unfortunately whileNetworkManager itself has supported WireGuard for some time, thissupport hasn't

I mentioned in yesterday's entry that at work I'm building a VPNserver that will support WireGuard .I'm quite happy with WireGuard in general and I think it has someimportant attractive features (such as the lack of 'sessions' ), but we won't be offering WireGuardfor general use. I would like to, but every time I even consider theidea, I run headlong into the problem of provisioning, specificallyof provisioning WireGuard clients in some way that ordinary people cansuccessfully set

I recently learned about lsmem , which isdescribed as "list[ing] the ranges of available memory [...]". Thesource I learned it from was curious why lsmem on a modern 64-bitmachine didn't list all of the low 4 GB as a single block (theywere exploring kernel memory zones , where thelow 4 GB of RAM are still a special 'DMA32' zone). To start with,I'll show typical lsmem default output from a

I tweeted :

Today's state of work-brain:
mkdir /tmp/fred
umask 077 /tmp/fred

Immediately after these two commands, I hit cursor-up to change the' umask ' to ' chmod ', so that I then ran ' chmod 077 /tmp/fred '.Fortunately I was doing this as a regular user, so my next actionexposed my error.

This whole sequence of commands is a set of mistakes jumbled togetherin a very Unix way. My

For a long time, systemd's version of udev has attempted to givenetwork interfaces what the systemd people call predictable orstable names. The current naming scheme is more or less documentedin systemd.net-naming-scheme ,with an older version in their Predictable Netwwork InterfaceNames wiki page. To understand how the naming scheme is applied inpractice by default, you also need to read the description of NamePolicy= in systemd.link(5) , andinspect the default .link file, '99

I've recently been writing (again) about Linux network interfacenames, this time what goes into udev's normal device names . This is a perennial topic inmany operating systems; people are forever wanting straightforwardand simple names for devices (networks, disk drives, and so on) andforever irritated that operating systems don't seem to be able todeliver this. Unix network device naming makes an illustrativeexample for everything that adds complexity even without hot-pluggeddevices.

Once upon a time the name

In many organizations, the life cycle of computer accounts istheoretically relatively straightforward. Your employees have anofficial HR start date, at which point their account comes intobeing, and eventually they will have a departure date, at whichpoint their account goes away. There are wrinkles, but you canmostly get away with driving your account system from HR data.Often it's explicitly a good idea to do this, to make sure thatpeople who are no longer employed also no longer have computeraccounts (or at

Last month, we discovered that recent versions of Bash and GNUReadline now default to special handling of pasting into them . This is called "bracketed paste" mode;it requires you to explicitly hit Return in order to have the pastedtext accepted and allows you to edit the paste before then. Locally, we have decided to turn thisoff for the root account, and I've also turned it off for my ownaccount. We have pragmatic reasons for our collective decision,and I also have a broad general

One of the nice things about urllib.parse (and itsPython 2 equivalent) is that it will deal with partial URLs as wellas full URLs. This is convenient because there are various situationsin a web server context where you may get either partial URLs orfull URLs, and you'd like to decode both of them in order to extractvarious pieces of information (primarily the path, since that's allyou can reliably count on being present in a partial URL).However, URLs are tricky