Networking Toolbox

Your companion for all-things networking

Featured

6

IPv4 Subnet Calculator

Calculate subnet masks, network addresses, broadcast addresses, and host ranges

CIDR → Mask

Convert CIDR notation (e.g. /24) to subnet mask format (255.255.255.0)

Contains (A ⊆ B)

Check if one IP set contains another

MAC Address Converter

Convert MAC addresses between formats and identify manufacturer from OUI database

DNS Query Performance

Compare DNS resolver speeds across multiple providers to find the fastest for your location

TLS Handshake Analyzer

Analyze TLS/SSL handshake timing breakdown with detailed phase information and certificate exchange

Lookups

44

DNS Lookup

Reverse DNS Lookup

DNS Propagation Checker

SPF Record Evaluator

DMARC Policy Checker

CAA Effective Policy

NS/SOA Consistency Check

DNSSEC AD Flag Checker

DNSSEC Validation Chain

DNS Blacklist Checker

AXFR Security Tester

DNS Query Performance

SOA Serial Analyzer

DNS Trace

Glue Check

SPF Flatten

HTTP Headers Analyzer

Redirect Trace

Security Headers Analyzer

CORS Policy Checker

HTTP Performance Analyzer

HTTP Compression Check

Cookie Security Inspector

TLS Certificate Analyzer

TLS Versions Probe

TLS ALPN Negotiation

OCSP Stapling

Cipher Presets

Service Banner Grabber

TLS Handshake Analyzer

CT Log Search

TCP Port Checker

HTTP Ping

BGP Route Lookup

IPv6 Connectivity Checker

ASN & Geolocation Lookup

MX Health Checker

SPF Policy Checker

DMARC Policy Checker

SMTP TLS Checker

Greylisting Tester

Domain RDAP Lookup

IP Address RDAP Lookup

ASN RDAP Lookup

Subnetting

5

IPv4 Subnet Calculator

IPv6 Subnet Calculator

VLSM Calculator

Supernet Calculator

Subnet Planner

DNS Tools

34

PTR Generator

Reverse Zone Generator

Reverse Zones Calculator

PTR Sweep Planner

A/AAAA Bulk Generator

CNAME Builder

MX Record Planner

SRV Record Builder

TXT Record Escape Tool

SPF Policy Builder

DKIM Key Generator

DMARC Policy Builder

CAA Record Builder

TLSA Generator

SSHFP Generator

SVCB/HTTPS Builder

NAPTR Builder

LOC Builder

RP Builder

IDN Punycode Converter

DNS Record Validator

TTL Calculator

EDNS Size Estimator

DNS Label Normalizer

Zone Linter

Zone Diff

Zone Statistics

Name Length Checker

DNSKEY Key Tag Calculator

DS Record Generator

NSEC3 Hash Calculator

CDS/CDNSKEY Builder

RRSIG Planner

CIDR

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IP Range to CIDR

CIDR Summarizer

CIDR Split

Next Available Subnet

Free Space Finder

CIDR Deaggregate

CIDR Compare

CIDR Allocator

CIDR Alignment

Wildcard Mask Converter

Ref

23

CIDR Notation Explained

VLSM in Plain English

Route Summarization / Supernetting

IPv6 Address Types & Key Prefixes

Common IPv6 Prefix Lengths

IPv4 in IPv6

IPv6 Privacy Addresses

Common Subnet Sizes

Network Classes (A/B/C)

Reserved IP Ranges

Special-Use IPv4 Blocks (RFC 6890)

Private vs Public IP Addresses

Carrier-Grade NAT Explained

Link-Local & APIPA Addresses

IPv4 & IPv6 Multicast Basics

Reverse DNS (PTR Records)

Reverse Zones for CIDR Delegation

ICMP & ICMPv6: Common Types

ARP vs NDP

What is an ASN?

Common TCP/UDP Ports

ACL Wildcard Masks

Common MTU/MSS Values