Short Tips and Fixes

Short Tips and Fixes

57 posts Find the best and most effective tips and fixes for everyday tasks. Whether you're looking for quick ways to fix a broken item, or just want to get the job done faster, this page has the solutions you need.

“Error: queue file write error” with Postfix and Amavis

Viewing Linux console screens

Using openssl instead of telnet to test HTTPS, POP3S connections

Unprivileged lxc containers and open file limit problem

Stale NFS handle

SSH exit codes

Source port routing

Simple filesystem read/write tracing with /proc/sys/vm/block dump

Simple file sharing with Samba 4

Shell: finding the biggest file on the server

Scripting qemu / kvm monitor

Rsync exit codes

Routing with multiple network cards

Resizing qcow2 images

Repairing broken PostgreSQL databases / tables

Problems starting elasticsearch in Ubuntu 16.04

PostgreSQL: create a user with password and assign it to a database

Poor write performance on Fusion MPT SAS RAID controllers

Plesk: "The specified limit is invalid" when trying to change mailbox quota

OpenSSH: tunnel-only user

OpenSSH: sftp-only chrooted user

Nginx: 413 Request Entity Too Large

Nginx HTTP basic auth – allowing IP or password-based access

MySQL: unattended Percona Server 5.7 installation

MySQL: split whole database dump into separate databases

MySQL: connecting to different ports on localhost

MySQL: changing ROW FORMAT to DYNAMIC or COMPRESSED

MySQL replication: adding a new database

Multiple shared IPs in WHM

Mongo: enabling user auth

Mdadm: stopping and starting RAID check in Linux

Java leap second bug – 30 June / 1 July 2012 – fix

IPv6: blocking incoming traffic with ip6tables

Iptables: LOG target not working in LXD containers

Hpacucli: Error: No controllers detected (with hpsa module in use)

GRE tunnel between two LXD hosts

Git clone: Problem with the SSL CA cert

Getting rid of “IPv6 addrconf: prefix with wrong length 56”

Generating DKIM key with OpenSSL

Generate SSL dhparam file with openssl

Ffmpeg video conversion command line examples

Enabling OpenVPN with systemctl

Enabling IPv6 on CentOS

Downgrading to PHP 5.3 on Debian Wheezy (7.0)

Disabling fan on Dell Precision 5520

Disable systemd listening on port 111

Disable / Enable Keyboard and Mouse in Linux

Decoding SSL certificates and signing requests with OpenSSL

Debian Lenny, /etc/apt/sources.list and error 404

Date conversion oneliners in bash

Bash: find and remove empty files and directories

AWS: IAM policy to allow EC2 volume snapshotting

Arcconf on Linux: examples

Apache: serving different robots.txt for SSL and non-SSL version of the website

Adding existing code to bitbucket

Accessing Windows console remotely from Linux

A quick SVN repository set up for your website

Great! You’ve successfully signed up.

Welcome back! You've successfully signed in.

You've successfully subscribed to Lxadm.com.

Success! Check your email for magic link to sign-in.

Success! Your billing info has been updated.

Your billing was not updated.