Cheat sheets, study guides, and practice tests built by engineers with real certifications.
Every Linux file permissions cheat sheet promises to make chmod click. Most just list commands. This one walks through the actual logic: how to read rwx in ls -l, how symbolic and octal notation map to each other, and the one mistake that wrecks a whole directory when you run chmod -R without thinking first.…
Need a Cisco commands cheat sheet that doesn't stop at the basics? This one covers over 200 IOS commands across switches and routers, grouped by topic so you're not hunting through a 12-page manual mid-lab. Hostnames and passwords. VLANs and trunking. OSPF, EIGRP and RIP. ACLs, NAT, DHCP, PPP and Frame Relay. If it's a…
Free network topology types PDF diagram set. Star, mesh, bus, ring, tree and hybrid layouts explained with pros, cons and real network examples. There are six network topology types you'll actually run into: bus, star, ring, mesh, tree and hybrid. Each one lays out how devices connect, and that layout decides speed, cost, and how…
Full CIDR table, /8 to /32: subnet mask, wildcard mask, total hosts, usable hosts - Powers-of-2 host reference - IPv4 classes A to E, private ranges, loopback - Six subnetting shortcut tips - Per-prefix "how many usable hosts" Q&A block
64 Linux commands on one page, grouped by what you're actually trying to do instead of listed alphabetically. Files and text, users and permissions, packages, processes, networking, and file transfer, each with a one-line description you can read in passing.
The page copy in `01-page-content.md` describes a 20-question practice test weighted to the real exam blueprint. That test doesn't exist as a file yet, the sent PDF is someone else's platform and someone else's attempt, not ours to reuse. This is the spec for what needs writing before the download behind this page is real.
It's 27 pages of CCNA 200-301 study notes with the Packet Tracer commands underneath every concept. All six exam domains: networking fundamentals, subnetting with the magic-number trick, VLANs and trunking, router-on-a-stick, STP, EtherChannel, static routing and OSPF, DHCP and NAT/PAT, ACLs and port security, wireless, and the automation topics.
It's 180 DevOps interview questions with short, say-it-out-loud answers, grouped by the tool the interviewer is holding. Built for anyone with a DevOps or platform engineer screen booked in the next two weeks.
This is a free 47-page PDF written by a working service provider network engineer, not a vendor marketing team. Every recommendation comes with the actual configuration, and most come in all three flavours: IOS, IOS-XE and IOS-XR side by side. If you're building an MPLS core, prepping for CCNP Service Provider, or you inherited a network someone else tuned badly, this is the reference you keep open in a second tab.
It's 50 CCNA-level interview questions with short, say-it-out-loud answers. OSI model, subnetting, VLANs and trunking, STP, DHCP and DNS, NAT and PAT, OSPF and BGP, ACLs, HSRP, QoS, and the troubleshooting questions that come up in every first-round screen. One question per block, one tight answer under it. Built for people walking into a junior network engineer or NOC interview in the next two weeks.
Free OSI model cheat sheet PDF. All 7 layers with functions, PDUs, devices and protocols, plus mnemonics and an OSI vs TCP/IP map.
It walks you through building a full Cisco SD-Access virtual lab for self-practice: Catalyst Center, ISE, and Catalyst 9000v switches running on EVE-NG and ESXi. You get the resource sizing, the topology, the connectivity map, and working config for the fusion router, NAT router, and border node. Built for CCNP Enterprise and CCIE candidates who want hands-on fabric practice without buying hardware.
