v2.0  ·  26 interactive tools

learn networks
interactively

Subnet calculators, OSI layers, HTTP request flows, port scanning — all in the browser. No installs, no signup, 100% client-side.

explore tools → devdunia.com ↗ echobash.com ↗
32
IPv4 bits
27
tools
80+
glossary terms
65K
ports indexed
$ netkit --analyze 192.168.1.0/24
ip address192.168.1.0
cidr prefix/24
network192.168.1.0
broadcast192.168.1.255
subnet mask255.255.255.0
usable hosts254
ip typePRIVATE (RFC1918)
nat requiredYES
your public ip detecting…
your private ip detecting…
11000000.10101000.00000001.00000000
← network (24 bits) ─────────── → host (8)
network 75% host 25%
tools
11000000.10101000
00000001.00000001
/24 → 254 hosts
⬡
Subnet Calc
CIDR visualizer, binary breakdown, subnet planner, IPv4 vs IPv6.
open tool →
[7] Application
[4] Transport
[1] Physical
◈
OSI Model
Explore all 7 layers, protocols at each level, and encapsulation flow.
open tool →
GET / HTTP/1.1
Host: example.com
← 200 OK
⇌
Request Flow
DNS → TCP → TLS → HTTP — step through every hop a request makes.
open tool →
22/tcp open ssh
80/tcp open http
443/tcp open https
⌖
nmap Explorer
Port scan concepts, common ports, TCP/UDP, command builder.
open tool →
en0: active
192.168.1.105/24
utun0: vpn
⎋
ifconfig Parse
Paste ifconfig output — get interfaces, IPs, subnets, and host ranges at a glance.
open tool →
80 → http
443 → https
22 → ssh
⊞
Port Reference
Search 60+ ports by number, name, or service. Filter by TCP/UDP and category.
open tool →
A → 1.1.1.1
MX → mail.google.com
NS → ns1.example.com
◎
DNS Lookup
Real DNS queries via Cloudflare DoH — A, AAAA, MX, CNAME, TXT, NS, SOA records.
open tool →
192.168.1.1
→ 0xC0A80101
→ 11000000…
⇄
IP Converter
Convert IPs between decimal, binary, hex, 32-bit integer, and reverse DNS — with bit visualizer.
open tool →
1 GB @ 100 Mbps
→ 80 seconds
1 TB → 22 hours
⇡
Bandwidth Calc
Transfer time calculator — file size + connection speed → how long will it take?
open tool →
00:50:56 → VMware
AC:DE:48 → Apple
OUI · NIC · type
⬛
MAC Lookup
OUI vendor lookup, broadcast/multicast detection, MAC format converter.
open tool →
2001:db8::1
fe80::1 link-local
expand · compress
⬡
IPv6 Tools
Expand, compress, and analyze IPv6 addresses — scope detection, prefix breakdown.
open tool →
SYN →
← SYN-ACK
ACK → ESTABLISHED
⟳
TCP Handshake
Step-by-step animated 3-way handshake and 4-way teardown with state machine.
open tool →
Eng: /26 (50h)
HR: /28 (10h)
WAN: /30 (2h)
▤
VLSM Allocator
Allocate variable-length subnets from a single address space — minimizes IP waste.
open tool →
ARP · BGP · CIDR
DNS · ICMP · MTU
NAT · TLS · VLAN
⋮
Network Glossary
80+ networking terms — searchable A–Z reference with explanations and related concepts.
open tool →
Content-Type: …
Strict-Transport…
X-Frame-Options
≡
HTTP Headers
Inspect HTTP response headers, security grading, and per-header explanations.
open tool →
ClientHello →
← ServerHello
Finished · keys
🔒
TLS Handshake
Deep step-by-step TLS 1.3 and 1.2 handshakes — key exchange, cipher suites, forward secrecy.
open tool →
IP-in-UDP tunnel
WireGuard · ChaCha20
without/with VPN
⊘
VPN Explainer
How VPNs work — tunneling, encryption, DNS leaks, split-tunneling, protocol comparison.
open tool →
Discover →
← Offer
Request → ACK
⊕
DHCP / DORA
Animated DORA exchange — packet fields, lease timers, T1/T2 renewal walkthrough.
open tool →
10.0.0.5:4321 →
203.0.113.1:6001
NAT table
⇔
NAT / PAT
Packet address translation step-by-step — PAT, static NAT, connection tracking table.
open tool →
Who has 10.0.0.3?
← 00:11:22:33:44:55
ARP cache
◉
ARP
ARP request/reply animation — broadcast, unicast reply, cache update, Gratuitous ARP.
open tool →
Class A: 1–126
Class C: 192–223
D: multicast
◑
IP Classes
Classful IP decoder — A/B/C/D/E detection, private ranges, loopback, APIPA, binary view.
open tool →
TCP: ordered ✓
UDP: fire-forget
headers · use cases
⇅
TCP vs UDP
Header structures, delivery guarantees, packet loss demo, and real-world use case cards.
open tool →
Hub: L1 flood
Switch: L2 MAC
Router: L3 IP
⬡
Network Devices
Hub vs Switch vs Router — OSI layers, forwarding logic, collision/broadcast domains compared.
open tool →
ping · traceroute
dig · tcpdump
nmap · ss · curl
$
Command Cheatsheet
Searchable reference for 16 network commands — Linux, macOS, Windows with examples.
open tool →
1 10.0.0.1 1ms
* * * timeout
RTT spike detected
⤳
Traceroute Parser
Paste traceroute output — get hop analysis, RTT colour-coding, timeout and spike annotations.
open tool →
VLAN 10 · 20 · 30
802.1Q tag: 12-bit
trunk · access
▦
VLAN Explainer
Access vs trunk ports, 802.1Q tagging, inter-VLAN routing, router-on-a-stick diagrams.
open tool →
KEX → ECDH
known_hosts · auth
tunnels · -L -R -D -J
🔒
SSH Explained
Full SSH deep-dive — handshake, public key auth, tunneling, ECDH crypto, and known_hosts.
open tool →