wget HowTo - Linux / Unix Q & A from nixCraft

FreeBSD wget cannot verify certificate, issued by Let’s Encrypt

last updated December 17, 2018 in FreeBSD, FreeBSD Jails (VPS), Troubleshooting, UNIX

I installed GNU wget utility on FreeBSD as explained here. However, whenever I use the wget command to download stuff from the Internet, it says:
ERROR: cannot verify download.freebsd.org’s certificate, issued by ‘CN=Let\’s Encrypt Authority X3,O=Let\’s Encrypt,C=US’:
Unable to locally verify the issuer’s authority.
How do I fix this problem on FreeBSD 12?

Install Speedtest-cli On a CentOS / RHEL / Fedora Linux To Check Internet Speed

last updated July 18, 2019 in CentOS, Fedora Linux, Linux, Networking, Python, RedHat and Friends

I do not want to use Adobe flash based speed testing site due to security concern on my desktop. How do I install Speedtest-cli on a CentOS Linux or Fedora Linux or Red Hat Enterise Linux (RHEL) for checking the Internet speed?

HowTo: Nginx Block User Agent

last updated June 27, 2012 in Nginx

How do I block a http user agent or a software agent using Nginx web server under Linux or Unix like operating systems?

Linux Download Password Protected Large ISO Images [ Authentication Credentials ]

last updated July 28, 2011 in Linux

I‘m trying to download an ISO image for Enterprise Linux from RHN or Novell Suse. Both providers have placed ISO images behind paywall. I need to provide authentication credentials before downloading all files. How do I download ISO files using the wget command with user name and password?

CentOS / Redhat Linux: Install OpenNTPD To Synchronize The Local Clock

last updated November 22, 2016 in CentOS, Fedora Linux, Linux, Package Management, RedHat and Friends

OpenNTPD is a Unix system daemon implementing the Network Time Protocol to synchronize the local clock of a computer system with remote NTP servers. How do I install OpenNTPD under CentOS / RHEL / Fedora Linux instead of default NTPD client / server?

PHP Add Captcha Protection To Web Forms

last updated September 22, 2009 in Anti Spam, Apache, CentOS, Debian / Ubuntu, Fedora Linux, FreeBSD, Linux, PHP, Programming, RedHat and Friends, Security, Windows

I own a small business website. However, bots started to abusing my forms such as contact.php. How do I stop bots bots from abusing my site? How do I tell if PHP form is submitted by a person or a script?

OpenBSD Install Ports Tree Collection

last updated November 9, 2016 in OpenBSD, Package Management, UNIX

I have installed OpenBSD operating system but ports collection is missing at /usr/ports directory. How do I install ports from ftp / http site under OpenBSD?