Working with USB in Virtualbox under a Linux host

To allow the use of USB, we must add the user to the vboxusers group, this can be done with:

sudo /usr/sbin/usermod -aG vboxusers $USER

substitute $USER for a user other than the current user if needed.

Also worth doing is adding a directory for VM's such as /DATA/VM

We should then change the group to vboxusers by:

sudo chgrp -R vboxusers VM

and also set the group inheritance by

sudo chmod g+s VM

this ensures that any new files also have the vboxusers group.

Visual Basic 6 and LF, forcing to git to use CRLF

When working with VB6 and uploading to GitHub, modify the .gitattributes file to look like the below:

# Default behaviour
* text=auto
# VB6 source files must stay CRLF
*.bas text eol=crlf
*.cls text eol=crlf
*.frm text eol=crlf
*.vbp text eol=crlf
*.vbg text eol=crlf
*.ctl text eol=crlf
*.dsr text eol=crlf
*.txt text eol=crlf
# VB6 binary companion files
*.frx binary
*.res binary
*.exe binary
*.ocx binary
*.dll binary

If doing retrospectively, then we should do the following:

git add --renormalize .

git commit -m "Fix line endings for VB6"

git add --renormalize .

git commit -m "Renormalize line endings"

git reset --hard

The following is a check to see if the files are LF or LFCR;

git ls-files --eol

Slackware minimum PXE boot example

For this example, we will be using dnsmasq on Slackware 14.2 with the Slackware 15 mirror.

crontab -e not opening correct editor

Open your .bashrc file and add the line export EDITOR=vim

Then logout and back in or source .bashrc

tcpdump

 TCPDUMP EXAMPLES

MariaDB Logging and old password support

For old password compatibility, do

SET GLOBAL old_passwords = 1;
SET PASSWORD FOR 'repl'@'%' = PASSWORD('the_password');
SET GLOBAL old_passwords = 0;

We can also try SET GLOBAL secure_auth=OFF; however I found this made no difference when running MariaDB 10.5 and attempting to connect with an old (presumable 4.1) client.

MariaDB GTID position reset

On Master, do SELECT @@gtid_current_pos;
then on Slave, do SET GLOBAL gtid_slave_pos = 'GTID_FROM_SERVER_1';

if need be do;

CHANGE MASTER TO
  MASTER_HOST='server1',
  MASTER_USER='replica_user',
  MASTER_PASSWORD='password',
  MASTER_USE_GTID=slave_pos;

then;

Start Slave;

SHOW SLAVE STATUS/G;

A note on the above, do it quickly, in case the position changes.

SELECT @@gtid_slave_pos, @@gtid_current_pos; should show the same.

Oracle timeouts

I had a problem with Oracle timeouts when connecting to a remote Oracle database server from within a php page. This resulted in the need to restart Apache to resolve as other web pages were also not available in said situations.

PCI Passthrough

WIP

Reboot and do: dmesg | grep -e DMAR -e IOMMU

[source]

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fail2ban-client

An example of the fail2ban-client command would be:

fail2ban-client status filter-name 

where filter name is the name of a file in /etc/fail2ban/filter.d/