After a four-year enforced pandemic-based hiatus, we were back for our latest installment of EMF in June with nearly 2,750 people on site. Back at Eastnor Castle deer park again this year, we were able to use the street cabinet and fibre around the field that we installed in 2018 to get up and running quickly once we arrived on site.
In a world where FTP has finally been turned off by most ISPs, Wordpress allegedly supports SSH2 for upgrades instead, using FS_METHOD ssh2. However it fails to work in any real-world scenario because it assumes the filesystem paths on the remote host are the same as on the local filesystem.
This obviously fails with pretty much any ISP on earth as the users are chroot()ed, so a directory that was once perhaps /home/david/www.davidc.net would in fact be just /www.davidc.net when accessed over SFTP.
This script allows you to check virtual users' Maildir sizes compared with the quota, and produces a simple list of addresses that are overquota, which can be used for example by mail delivery agents to reject incoming messages when the user is overquota.
Computerphile interviewed me about the EMF temporary network that we build up in a field for the festival and tear down the next week. You can watch the interview on YouTube!
I seem to be spending a lot of my time recently hacking around RouterOS bugs. Here's a script that monitors the state of the PPP interface for a GSM modem and does what it can to get it back up and running if necessary.
The script checks three times (10 seconds apart) to see if the PPP interface is connected. If it still isn't, it resets the USB power to try and kick the communication back to life. It waits 30 seconds after doing this then, if it's still not up for two more checks, it reboots the whole Routerboard.
New site, new challenges! Electromagnetic Field 2018 was held at Eastnor Castle Deer Park towards the end of summer and we faced a new set of challenges - some of which we set ourselves. This year we liked the potential of the site so much, we started in January by installing our very own street cabinet for the incoming circuit and ran ducts out to the street.
RouterOS has no native concept of fallback PPPoE credentials. You can only enter one username and password per interface. Sometimes you would like to enter a fallback set that are tried if the primary credentials don't work, for example to prepare for a migration. Here is a RouterOS script to handle fallback PPPoE credentials that will be tried one after another until one set succeeds.
Acrobat's automatic form generation is atrocious. It inevitably gets almost everything wrong, meaning you have to recreate it by hand. It boggles the mind that it's had the ability to create forms for 20 years now, and still has no way of automatically creating the form from a Word document without a buggy and and half-hearted attempt at auto-detection. You'd think at the very least it would be able to turn Word form elements into PDF form elements, but no.
qmail-remove provides a means to easily remove messages from the Qmail queue, but restoring messages is rather more complicated. Here is a quick shell script that will allow messages to be correctly restored, undoing the yank.
Customers wishing to use their own router with VDSL2 (FTTC) services in Germany are hampered by the CPE not supporting PPPoE passthrough, as Telekom limits the line to 1 PPPoE session. The CPE therefore needs to be replaced entirely. This article describes how to extract the login information from an O2 Homebox and then configure a Cisco router as a replacement CPE.