Endless CCNA-style practice: network addresses, broadcasts, host counts, and VLAN-range questions with explanations.
Subnet / CIDR Calculator · Bandwidth-Delay Product Calculator · Availability / SLA Calculator · Data-Center Capacity Planner · Tick-to-Trade Latency Calculator · Optical Link Budget Calculator · PTP Timing Budget Calculator · ECMP Hash Polarization Visualizer · Firewall ACL Rule Analyzer · Network config verifier · PTP/SyncE Network-Wide Timing Simulator · Wireshark Display Filter Builder · Wi-Fi Channel Interference Planner · QoS Token-Bucket Policer & Shaper Simulator — all free, all run entirely in your browser.