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INTERACTIVE LEARNING TOOL

Protocol Explorer · IP

Explore internet protocols with animated messages, real arrival order and packet inspection.

Read the learning guides ↓
PROTOCOL EXPLORERLearn how the internet works
Now learningIP · Addressing & routingOverview · 4 steps
Learning progress0%
0 / 14 complete · 0 in progress
Client192.168.1.10Router192.168.1.1InternetWeb Server203.0.113.10

Protocol overview

IP

Active

Internet Protocol

Follow an IPv4 packet through a router. IP supplies addressing and best-effort routing; transport protocols supply ports and additional delivery behavior.

Layer
Network (Layer 3)
Default port
No ports
Transport
Link layer
Data format
Addressed network packets
Defined in
RFC 791, RFC 8200
Read the complete guide ↗

Packet flow

DNSTCPRequestResponse
No.TimeSourceDestinationProtocolInfoSize
10.000s192.168.1.10203.0.113.10IPLocal frame to gateway · TTL 6460 B
20.024s192.168.1.10203.0.113.10IPForwarded frame · TTL 6360 B
30.048s192.168.1.1192.168.1.10ICMPFragmentation needed · next-hop MTU 150070 B
40.072s203.0.113.10192.168.1.10IPReply delivered to transport60 B

NAVSPROUT · PROTOCOL FIELD GUIDES

IP, packet by packet.

Follow an IPv4 packet through a router. IP supplies addressing and best-effort routing; transport protocols supply ports and additional delivery behavior.

PROTOCOL FIELD GUIDE

How IP works

Follow an IPv4 packet through a router. IP supplies addressing and best-effort routing; transport protocols supply ports and additional delivery behavior.

Default port
No ports
Transport / carrier
Link layer
Category
core

1. Choose a next hop

A host compares the destination with its local subnet. Off-subnet traffic is sent to a default gateway at the link layer.

2. Forward across a router

A router selects a route using the destination prefix and decrements TTL. Link-layer addresses change at a routed hop.

3. Respect the path MTU

An IPv4 router can fragment if permitted. With DF set, an oversized packet is dropped and an ICMP error can help path MTU discovery. IPv6 routers do not fragment.

4. Deliver to transport

The destination uses the IP Protocol field to choose TCP, UDP or ICMP. This IPv4 example uses 6 for TCP.

Protocol relationships

Protocols cooperate across layers. Compare the neighboring lessons to distinguish addressing, delivery, application semantics and encryption.

Standards and editorial method

Written and implemented independently by NavSprout. Lessons summarize public protocol standards using synthetic documentation addresses and fictional credentials. Consult the standards for complete wire formats and normative behavior.

RFC 791 ↗ RFC 8200 ↗

Check your understanding

Which field prevents an IPv4 packet from looping indefinitely?

Why it’s hereNAVSPROUT ORIGINAL

Reading definitions is easier when you can connect them to a packet. This first-party learning tool pairs static explanations with a visual lab, byte inspection and a short knowledge check. All course data and application resources ship with NavSprout.

  1. Choose DNS and follow the lookup from client to authoritative server.
  2. Switch to the sequence view, then inspect a packet and select a field to highlight its bytes.
  3. Compare TCP with UDP, answer the quiz and export your progress.

Frequently asked questions

What happens when I open a website?

A typical first HTTPS visit can involve DNS resolution, a transport connection, a TLS handshake and an HTTP exchange. Caches, connection reuse and HTTP/3 can change this sequence.

How are TCP and UDP different?

TCP presents a reliable ordered byte stream. UDP preserves individual datagram boundaries without built-in delivery guarantees. Applications choose the behavior they need.

Are these real captured packets?

No. Frames are generated locally for teaching. Header lengths and checksums are calculated, while TLS ciphertext and some negotiation payloads are illustrative. Downloaded PCAP files contain synthetic examples, not live traffic.

Can I learn without JavaScript or an account?

All 14 protocol guides and their lesson explanations are available as ordinary HTML without signing in. JavaScript powers animations, byte inspection, local progress and quizzes.

Where is my progress saved?

Only in this browser’s local storage. Export a progress JSON file to move it to another device. Clearing browser data can remove progress.

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