In this series, we’re looking at some important considerations for sysadmins who want to expand their skills and advance their careers. The previous article provided an introduction to the concepts we’ll be covering, and this article focuses on one of the fundamental skills that every sysadmin needs to master: networking.
Networking is a complicated but essential core competency for sysadmins. A good sysadmin understands:
How users connect to a network, including managing remote connections via a Virtual Private Network (VPN)
How users authenticate to a network, ranging from standard two-factor authentication, to custom authentication requirements
How switching, routing and internetworking work
Software-Defined Networking (SDN)
TCP/IP (Transmission Control Protocol/Internet Protocol) forms the basis of how devices connect to and interface with the Internet. Sysadmins understand how TCP/IP packets address, route, and deliver data across a network.
A good sysadmin also knows how domain name servers (DNS) and resource records work, including understanding nameservers. They typically are fluent with DNS query tools such as dig and nslookup, as well topics such as sender policy framework and NOTIFY.
With large-scale security threats continuing to emerge, there is now a premium on experience with network security tools and practices. That means understanding everything from the Open Systems Interconnect (OSI) model to devices and protocols that facilitate communication across a network. Locking down security also means understanding the infrastructure of a network. Securing a network requires competency with routers, firewalls,VPNs, end-user systems, server security, and virtual machines.
Additionally, knowledge of a platform like OpenStack can effectively expand any sysadmin’s networking clout, because OpenStack, CloudStack, and other cloud platforms essentially expand the perimeter of what we think of as “the network.”
Likewise, the basics of software-defined networking (SDN) are increasingly important for sysadmins to understand. SDN permits admins to programmatically initialize, control, and manage network behavior dynamically through open interfaces and abstractions of lower-level functionality. This, too, is a category where familiarity with leading open source tools can be a big differentiator for sysadmins. OpenDaylight, a project at The Linux Foundation, is an open, programmable, software-defined networking platform worth studying, and OpenContrail and ONOS are also on the rise in this space.
Additionally, many smart sysadmins are working with open configuration management tools such as Chef and Puppet. Julian Dunn, a product manager at Chef, writes: “System administrators have got to stop thinking of servers/disk/memory/whatever as ‘their resources’ that ‘they manage.’ DevOps isn’t just some buzzword concept that someone has thought up to make sysadmins’ lives hell. It’s the natural evolution of both professions.” See our list of relevant, open configuration management tools here.
For sysadmins who want to learn more about networking, the good news is that training in this area is very accessible and, in some cases, free. Furthermore, excellent free and open source administration and configuration tools are available to help boost any sysadmin’s networking efficiency.
Training options for Linux-focused sysadmins include a variety of networking courses. For sysadmins, CompTIA Linux+ offers solid training options, as does the Linux Professional Institute. The Linux Foundation Certified System Administrator (LFCS) course is another good choice. The Linux Foundation offers the LFS201 basic course and LFCS exam. Many vendors in the Linux arena also offer networking-focused training and certification for sysadmins, including Red Hat.
It’s also worth checking out O’Reilly’s Networking for Sysadmins video training options. These videos cover TCP/IP basics, OSI, and all the essential components within a network’s infrastructure, ranging from firewalls to VPNs to routers and virtual machines. The information is comprehensive, with some of the individual videos requiring a full day to complete and digest. Additionally, the curriculum is available on demand, so it can be used as reference material for networking essentials.
Additionally, Lynda.com offers an array of online network administration courses taught by experts. Sysadmins can quickly get through courses such as Linux File Sharing Services and Identity and Access Management.
Even as sysadmins focus on moving up the technology stack with their skillsets, networking basics remain essential. Fortunately, training and education are more accessible than ever. Next time, we’ll look at important security requirements to consider when advancing your sysadmin career.
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