Network Tools
50 free tools for network engineers, DevOps, MSPs, cloud architects and students, grouped by the job you're doing. Everything runs in your browser, with no signup.
Tip: press Ctrl K anywhere to jump to a tool or paste an IP.
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Plan a network
Size and split address space.
- Subnet Calculator IPv4 CIDR & subnet masks
- CIDR Calculator Prefix breakdown & split into blocks
- Subnet Mask Calculator Mask ↔ CIDR ↔ wildcard converter
- VLSM Calculator Variable length subnet masking
- Supernet Calculator CIDR aggregation & route summary
- CIDR to IP Range Convert CIDR notation to a range
- IP Range to CIDR Start–end range to exact CIDR list
- IPv6 Subnet Calculator IPv6 prefix & address ranges
- Route Summarization Optimal CIDR aggregation for BGP
Cloud & Kubernetes
Reserved IPs, pods and VPCs.
- AWS Subnet Calculator VPC reserved IPs & CIDR planning
- Azure Subnet Calculator VNet reserved IPs & subnet sizing
- GCP Subnet Calculator VPC reserved IPs & usable hosts
- EKS Max Pods Calculator Max pods per node, all instance types
- GKE Max Pods Calculator Alias IP ranges & VPC-native sizing
- Kubernetes Pod & Service CIDR Cluster CIDR sizing & overlap check
- CNI IP Pool & Block Size Calico/Cilium pool sizing
- EKS Multi-AZ Subnet Splitter VPC subnets per availability zone
- Terraform VPC Subnet Planner cidrsubnet() planner with HCL export
Check & audit
Catch conflicts before they ship.
Troubleshoot & look up
Test paths, ports and names.
- What Is My IP Your public IP, ISP & location
- Ping Test Ping from global locations
- Traceroute Trace network path hop by hop
- MAC Address Lookup Vendor (OUI), random & virtual MACs
- Port Checker Check if a TCP port is open
- ASN Lookup AS owner, prefixes & type
- IP Geolocation Locate any IP address
- VPN / Proxy Detector Detect VPN, datacenter & Tor IPs
- Routing Simulator Interactive routing table
DNS & email
Records, propagation and mail auth.
Learn & convert
Masks, binary, QoS and automation.
- Subnetting Practice Random questions with visual answers
- Cheat Sheets (PDF) Printable subnet, wildcard & IPv6 sheets
- Wildcard Mask Calculator Subnet ↔ wildcard for Cisco
- IP Converter Decimal, binary, hex, CIDR
- Bandwidth Calculator Speed & transfer time conversions
- MTU / MSS Calculator Stacked tunnel overhead & MSS clamp
- DSCP / QoS Converter DSCP ↔ ToS ↔ binary conversions
- IPv6 Compression Calculator Compress, expand & check IPv6
- IPv6 to IPv4 Converter Find embedded IPv4 addresses
- Random IPv6 Generator Test & example IPv6 addresses
- MAC to IPv6 (EUI-64) Link-local address from any MAC
- YANG Module Checker Validate YANG syntax & explore nodes
- Jinja2 Template Tester Render network config templates
Subnet reference pages
Mask, hosts and a worked example for each prefix, plus the ranges that cause most real-world clashes. Learning? Try the subnetting practice trainer or print a cheat sheet.