Interactive Simulators
Networking concepts only make sense when you can move them. These run in your browser — slide a CIDR mask, send a frame through a trunk, watch STP converge. No installs, no Packet Tracer required.
Subnetting Visualizer
Practice quiz on top. Below: slide a CIDR prefix and watch network, broadcast, host range, masks and the 32-bit boundary update live. VLSM splitter included.
Open simulator →OSPF Neighborship
Cisco-IOS-style neighbor state machine. Click Advance Handshake, watch Hello/DBD/LSR/LSU envelopes move between R1 and R2, with live IOS syslog, packet analyzer, and show commands. Includes Hello mismatch + ACL block + MTU mismatch troubleshooting scenarios.
Open simulator →Standard ACL
Configure a numbered or named standard ACL on an interface, send test traffic, see permit/deny verdicts and matching IOS syslog. Includes implicit deny visualization and common-pitfall scenarios.
Open simulator →Extended ACL
Practice extended ACL syntax: protocol + source + destination + port. Build the entry, apply it, then run packets through and see which rule matches. Console output, ACL hit counters, and worked traffic scenarios.
Open simulator →VLAN + Trunk Frame Walkthrough
Send a frame from one PC to another across a switch trunk. Watch the 802.1Q tag get added on ingress and stripped on egress, with native VLAN and inter-VLAN scenarios included.
Open simulator →Want this drilled into reflex?
1:1 mentorship around real labs, live debugging, and US interview prep. Free first session.