I've worked with a good number of Linux distributions over several years, Starting out with CentOS and now focusing more on using Debain and Ubuntu. I've been using Linux longer than I can remember, however it's been well over five years at the least
I have experience with Xen and VMWare, using both to put wide arrays of operating systems including Windows in virtual enviroments. I have also worked with various other systems like Docker or OpenVZ, however I've worked with them less than bare metal virtualization solutions like Xen
I'm capable of desiging and laying out networks for various needs. I have light experience with commercial routers like Cisco and have worked with many different kinds of managed switches including ones from HP. I have even more experience working with residential routers and modems for various tasks. I definitely know the difference between Cat5, Cat5e, or Cat6, a Switch, Router, or Modem, and UDP or TCP.
I've worked with Nginx and Apache on many ocassions, having spent most of my time with Nginx I've written config generators for it, twice. I've used Nginx for load balancing and acting as a proxy for various things along with just a standard webserver.
I run my own Bind9 DNS servers around the globe both for nameservers with immediate replication to all servers and quite a few domains, and a few as local dns servers for clients. Dynamic DNS Updating and advanced configurations are also things I've played with in my time with Bind9
Being in both programming and web development I've had to work with a wide number of database formats such as MySQL, MiriaDB, RethinkDB, Redis, SQLite, and MongoDB. My current favorite at the moment is RethinkDB and I use it extensively for all my new projects
Being a Systems Administrator I've learned that automation is key. I spend the time required automating a task if I know it will cost me more time in the long run, and sometimes just to see if I can do it. I've worked with automation software like Jenkins CI and I write automation tools primarily in Bash, and Python and even sometimes a mix of both.