How to remove duplicate packages with yum

I’m working on a handful of servers that all have the same problem: when running yum, an error message appears that tells me a package called ntpupdate needs to be upgraded, but somehow this doesn’t work and the package is being skipped. Then follows a huge list of duplicate packages that are installed on those systems (probably installed by the automatic package updater within Plesk).

Let’s see how we can fix such issues.

Read more

What’s the difference between the Logitech M325 and the M325c

The Logitech M325 and M325c are both wireless USB mice. Their design appears to be identical (except for the many different colourful variations of course), and their prices vary from anything between $12 and $60 – depending the layout and seller. Even the packaging is identical. So what’s the difference between these two models? Is … Read more

How to check which web server is running on a domain

Sometimes we must know what web server is running on a particular domain. Usually web hosts should be able to tell a client this, but if the client is afraid to ask, there is a way to ask the web server directly for this information.

Just to clarify: the web server is the process that serves files (HTML, PHP, ASP, images, etc) from a remote machine to your local web browser. The most likely choices in this day and age (2017) are Apache, NGINX or IIS. The latter is used by Windows servers, and the two former are used by Linux servers. There are other web servers too, such as lighttpd, but they’re used less commonly.

By asking the web server for this information, we can tell exactly who’s serving those files.

How to ask the Web Server

Let’s open a Terminal or Command Line Prompt window and utilise the good old fashioned Telnet protocol. Replace with the actual domain in question:

Read more