Ubuntu

5th April 2023

While using letsencrypt it was throwing following error

Failed authorization procedure. (http-01) :urn:ietf:params:acme:error:dns  :: DNS problem: NXDOMAIN looking up A for  - check that a DNS record exists for this domain; DNS problem: NXDOMAIN looking up AAAA for - check that a DNS record exists for this domain

Had tried following commands to install letsencrypt but above error was thrown

sudo add-apt-repository ppa:certbot/certbot

sudo apt-get update

apt install python-certbot-apache

certbot --apache -d xx.xxx.xxx.xx

The following command helped to solve the above error and successfully install letsencrypt with domain

certbot --apache -d xx.xxx.xxx.xx --debug-challenges

1st February 2023

While adding gpg key if you are behind proxy many times the key will not come on desktop if you use following command key will get downloaded

apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --keyserver-options http-proxy=http://x.x.x.x:xxxx --recv-keys 1655A0AB68576280

This is useful when you want to also get Node.js either 14.x or 16.x

22nd October 2019

On ubuntu 16.04 desktop the system was showing wrong date and time. Struggled a lot then made changes in BIOS settings but still the time was showing wrong. By running the following command, system was showing correct time and date.

timedatectl set-local-rtc 1 --adjust-system-clock

14th May 2018

To adjust time on Ubuntu installation of 16.04 run the following command.

timedatectl set-timezone UTC 

and the system will show correct time.