The short version that you need, the rest is nice to know but this is your bread and butter. screen (starts a new session) this is once off until you destroy it or server/system restart. CTRL+A (then release both) then press D will put the session into the back. screen -r (will reconnect you to […]
Keep System Up-To-Date An extremely crucial part of hardening any system is to ensure that it is always kept up-to-date. Doing this will keep any known bugs or vulnerabilities patched if one exists. The following commands are ways to update an Ubuntu system:apt-get update && apt-get upgrade Accounts A good place to start when dealing […]
Ubuntu The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY B53DC80D13EDEF05 GPG error: http://packages.cloud.google.com/apt google-cloud-monitoring-focal-all InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY B53DC80D13EDEF05 i.e. for this specific key “B53DC80D13EDEF05” being reported Run the following command Executing: /tmp/apt-key-gpghome.5ZVvtULX98/gpg.1.sh –keyserver hkp://keyserver.ubuntu.com:80 –recv-keys B53DC80D13EDEF05gpg: key […]
checklist for SysAdmins This article includes a collection of commands and best practices that you can use to improve the security of your Linux servers (RHEL/CentOS) 1. Remove insecure tools (FTP, telnet, rlogin, rsh, etc.) and use only secure alternatives (SCP, SSH, sftp, rsync, etc.) When choosing data communication tools, use only the secure and […]
Re-calculate a checksum for monit After an update you will probably receive the monit checksum failed notification. Most likely Apache if you have added the additional repo for latest updates. check file apache_bin with path /usr/sbin/apache2 if failed checksum then unmonitor It is a quick fix and the error is correct. The documentation isn’t very clear […]
Create an @reboot entry in your crontab to run a script called /usr/local/bin/runonce. Create a directory structure called /etc/local/runonce.d/ran using mkdir -p. Create the script /usr/local/bin/runonce as follows: Now place any script you want run at the next reboot (once only) in the directory /etc/local/runonce.d and chown and chmod +x it appropriately. Once it’s been […]
Setting the following command in a cronjob will ensure the remote folder is backed up to the location set and it keeps 1 old version of the file if it finds the original file has been changed. If you need to exclude files like logs then add the –exclude option rsync -arWPb –exclude=’access**’ username@serveraddress:/remote/location/ /destination/on/currentmachine/
