IT

OUCS VPN

Install:

  1. The AnyConnect VPN Client for Linux is available from the OUCS Software downloads page for Linux; see release notes for details.
  2. Unpack the downloaded file using an archive manager or type tar -xzvf filename from a terminal window (replacing filename with the file’s name).
  3. In a terminal window, navigate to the newly created directory beginning ‘anyconnect’, then to the VPN directory.
  4. Start the installation by typing sudo ./vpn_install.sh

Connect:

  1. To start the client either: • Select Cisco AnyConnect Secure Mobility Client from the Applications menu.
    • Type vpnui at the command line in the installation directory (for Ubuntu this is /opt/cisco/bin).
  2. Provide vpn.ox.ac.uk then Connect.
  3. Provide your Oxford username in the format abcd1234@ox.ac.uk and your Single Sign-On (SSO) password.

Disconnect:

  1. Select the VPN icon in the system tray.
  2. Select Disconnect.

Advanced settings:

The Cisco AnyConnect VPN client requires an SSL tunnel (TCP port 443) and optionally a DTLS tunnel (UDP port 443).

VPN clients contact the VPN servers in the netblock 192.76.7.64/27.

VPN clients will be given an IP address from the private IP ranges of 10.1.32.0/20 or 10.10.64.0/18.  These private addresses will be mapped to a public IP in the 129.67.116.0/22 netblock by the use of dynamic PAT.

Further details are available on the OUCS VPN page.

Disable snap and switch from snap to deb packages for Firefox in Ubuntu 22.04

Disable snapd

Remove Firefox (and other) snap packages:

snap list
snap remove firefox

Stop snapd service:

systemctl stop snapd.service
systemctl stop snapd.socket
systemctl stop snapd.seeded.service
systemctl disable snapd.service
systemctl disable snapd.socket
systemctl disable snapd.seeded.service

Remove snap related packages and directories:

apt autoremove --purge snapd chromium-browser* chromium-browser-l10n* gnome-software-plugin-snap* liblzo2-2* snapd* squashfs-tools*
rm -rf /var/cache/snapd
rm -rf /root/snap/
rm -rf /snap /var/snap /var/lib/snap

Install non-snap version of Firefox

Disable snap version

nano /etc/apt/preferences.d/mozilla-firefox
Package: firefox*
Pin: release o=Ubuntu*
Pin-Priority: -1
add-apt-repository ppa:mozillateam/ppa
apt update
apt install firefox
How to Install Latest Firefox as classic Deb in Ubuntu 22.04 | UbuntuHandbook
https://ubuntuhandbook.org/index.php/2022/04/install-firefox-deb-ubuntu-22-04/

How to Install Firefox as a .Deb on Ubuntu 22.04 (Not a Snap) - OMG! Ubuntu!
https://www.omgubuntu.co.uk/2022/04/how-to-install-firefox-deb-apt-ubuntu-22-04

Change X11 window title

A typical use case is when an editor is setting its window title to the full long path name such that the actual important part, the file name, falls off the edge on the right and becomes invisible. Unfortunately the X11 window title is normally set internally by the application and its format is hard coded. A solution is to monitor the editor window title and modify it if its becomes too long.

Continue reading Change X11 window title

Repartition a new USB drive

I want to use my new USB drive exclusively with Linux, so I decided to wipe the factory default partitions and create a new ext4 filesystem on the drive. The drive uses 4096 byte physical sectors and we have to make sure that the new partition is correctly aligned. For some background information on partition alignment, see this link.

Check that we are wiping the correct drive

sudo parted /dev/sdb unit s print free

Note the details in case you want to restore the original partitioning scheme. Information on the factory default can also be found here.

Continue reading Repartition a new USB drive

Atril (evince, document viewer) default directory for Save As

For the XFCE desktop environment Atril is the default PDF viewer and I also use it to open any PDF files from Firefox. It is a great lightweight document viewer which does what I need most of the time. One exception is when after opening a PDF file from Firefox I decide to keep the file and select File Save As. Atril insists on saving the file in $HOME/Documents, which is practically never the directory I want to use…

Continue reading Atril (evince, document viewer) default directory for Save As

Disable annoying XFCE automatic maximise window feature

In XFCE when you move a window around and it gets close to the top edge of the screen it suddenly jumps to maximised size – this is never what I want and so I find this feature really annoying.

The setting where this feature can be turned off is hidden in a somewhat counter intuitive location:

Yes, the setting is called ‘Accessibility – Automatically tile …’!

Fix for packet loss and latency problems with Virgin Media cable connections

About ten days ago my network connection with Virgin Media started to play up. I was experiencing significant packet loss, at times in excess of 50%, and increased latency times with peaks at more than 100ms.

Continue reading Fix for packet loss and latency problems with Virgin Media cable connections

Recovery of scanned PDF corrupted by email transfer

Occasionally when my scanner is emailing me a PDF it gets corrupted along the way. Most of the time the individual scanned images in the PDF are either perfectly valid or at least can viewed, even though the PDF viewer refuses to open the corrupt PDF file.

The bash script below will extract the images and then combine them again into a valid new PDF file.

Continue reading Recovery of scanned PDF corrupted by email transfer

Certwatch SSL certificate expiry warning

If you have just received an e-mail similar to the one below, read on.

From: root@your.domain.org To: sysadmin@your.domain.org Subject: The certificate for server.your.domain.org will expire in 13 days Date: yesterday (BST) ################# SSL Certificate Warning ################ Certificate for hostname ‘sws.hlan.laczik.org’, in file (or by nickname): /etc/pki/tls/certs/localhost.crt The certificate needs to be renewed; this can be done using the ‘genkey’ program. Browsers will not be able to correctly connect to this web site using SSL until the certificate is renewed. ########################################################## Generated by certwatch(1)
Continue reading Certwatch SSL certificate expiry warning

Special character mangling in WordPress and SyntaxHighlighter

The SyntaxHighlighter WordPress plug-in is used to display code ‘as is’; unfortunately WordPress again is too clever for its own good and mangles special characters like & and ” even before the text gets to the SyntaxHighlighter blocks in the Block Editor.

The solution is to add a filter function in your custom functions.php file:

Continue reading Special character mangling in WordPress and SyntaxHighlighter