Thoughts, stories and ideas.
How to instantly add known_hosts entries for host and its IP address
scheduled for 29 April 2019
How to inspect Redis internals using UNIX socket and Python script
scheduled for 01 May 2019
How to compare two files byte by byte
scheduled for 06 May 2019
Global known_hosts file located in /etc/ssh/ssh_known_hosts and user managed ~/.ssh/known_hosts contains known host public keys. Due to its nature these files can contain multiple entries using the same key. It is not a problem, but merging entries using the same key is the first step that is necessary to inspect it visually and to verify host entries.
Disconnect idle SSH clients using built-in client alive mechanism.
Learn how to erase LUKS header on a specific device.
Monitor PHP-FPM (FastCGI Process Manager) pool using curl utility, cgi-fcgi application or slightly modified Python script that was used to display PHP-FPM pool information.
Learn how to test LUKS passphrase on a specific device.
Match certificate and its private key by comparing the modulus of the certificate to the modulus of the private key.
I have already described how to check external IP address using curl or your own SSH service, but you can also use dig utility to take advantage of the OpenDNS, Google or Akamai DNS service.
Determine maximum LUKS key file size or maximum interactive passphrase length.