Networking Tools
11 free tools built for network engineers. No sign-up, no ads, no nonsense. All computation runs locally where possible.
Calculator
Subnet & CIDR Calculator
Enter any IP and prefix. Get network address, broadcast, host range, wildcard mask, binary breakdown, and a plain-English explanation of why this mask was chosen.
Calculator
VLSM Calculator
Give it a base network and your host requirements per subnet. Get optimal allocations automatically — largest first, zero waste. Includes address usage bar.
Lookup
IP & ASN Lookup
Paste any IP — get ASN, owner, country, ISP, coordinates. Automatically identifies private, bogon, and loopback ranges without an API call.
Visualizer
BGP Path Selection Visualizer
Add 2–6 BGP paths to the same prefix. See which path wins and exactly why — walking through all 13 BGP decision attributes in order.
Generator
BGP & OSPF Config Generator
Fill in your parameters, get a clean production config for Cisco IOS, IOS-XR, or Juniper JunOS. BGP, OSPF, and static routes.
Checklist
Troubleshooting Checklist
Pick your symptom — BGP down, can't ping, OSPF not forming. Get OSI-layer-by-layer steps with exact IOS commands. 20 years of debugging methodology.
Calculator
QoS & Bandwidth Calculator
Enter link speed and traffic classes. Get per-class bandwidth allocation, oversubscription warnings, and complete IOS policy-map and class-map config.
Builder
ACL Builder
Build standard and extended Cisco ACLs visually. Named or numbered, with remarks. Get clean IOS syntax ready to paste into the CLI.
Security
Cisco Password Hasher
Generate type-5 (MD5) and type-7 hashes for Cisco configs. 100% local — nothing leaves your browser. Includes password strength check.
Interactive
Certification Roadmap
Interactive visual paths from CCNA to CCIE, AWS Solutions Architect, and Python automation. Click any cert for exam cost, study hours, and what it covers.
Simulator
Ping & Traceroute Simulator
Educational simulator showing how ping and traceroute work — TTL mechanics, ICMP types, hop-by-hop path discovery with animated visualisation.
Photography
Exposure Triangle
Adjust aperture, shutter speed, and ISO. See EV, equivalent exposures, and what each setting does to your image — motion, DOF, noise.
Photography
Depth of Field Calculator
Enter focal length, aperture, sensor size, and subject distance. Get near/far focus limits, total DOF, hyperfocal distance, and visual focus zone.
Photography
ND Filter Calculator
Enter base exposure and ND filter strength. Get new shutter speed instantly. Stack multiple filters and see the combined stop value.
Photography
Golden Hour Calculator
Enter coordinates and date. Get exact golden hour, blue hour, sunrise, and sunset windows — with a visual 24-hour timeline and countdown to next shoot window.
Photography
Shot List Builder
Build a structured shot list before your shoot. Organize by type (aerial, portrait, detail), add notes, check off on location, and export to text.
Photography
Aspect Ratio & Crop Calculator
Enter source resolution and target ratio. See crop dimensions, megapixel loss, visual crop preview, and a table of all common output formats.
Reference
Cisco CLI Cheatsheet
180+ commands across 10 categories — BGP, OSPF, interfaces, NAT, ACL, VLANs, hardening, troubleshooting. Search or filter by topic. Click any command to copy.
Formatter
JSON & YAML Formatter
Format, validate, and convert between JSON and YAML. Minify, sort keys, detect type automatically. 100% local — nothing sent anywhere.
BGP
BGP Community Builder
Build and decode standard, extended, and large BGP communities. Well-known communities (no-export, blackhole, graceful-shutdown) with IOS config output.
AI
LLM Token Counter
Count tokens for Claude, GPT-4, Llama, Gemini. See context window usage percentage and cost estimates per model. All local.
Networking
MTU & Fragmentation Calculator
Select interface MTU and tunnel overheads (GRE, IPsec, MPLS, VXLAN). See usable payload, whether fragmentation occurs, and the MSS clamp value to fix it.
Calculator
IPv6 Subnet Calculator
Enter any IPv6 address and prefix. Get expanded/compressed form, network address, host range, type classification (ULA, link-local, global unicast), and 128-bit binary breakdown.
Comparison
Config Diff Tool
Paste two configs and see exactly what changed — added, removed, and unchanged lines. Unified or side-by-side view. Perfect for before/after maintenance windows.
Encoding
Base64 & Hex Encoder
Encode and decode Base64, URL-safe Base64, hex, and URL encoding. Plus SHA-256, SHA-1, and MD5 hashes. All local — nothing sent anywhere.
Dev Tool
Regex Tester
Live regex testing with match highlighting and capture group extraction. Preloaded with 16 network automation patterns for parsing show output, IPs, interfaces, and syslog.
Photography
Field of View Calculator
Enter sensor format and focal length. Get horizontal, vertical, and diagonal angle of view. Equivalent focal lengths across all sensor formats — full frame, APS-C, Micro 4/3, 1-inch, and more.
Calculator
IPv6 Subnet Calculator
Enter any IPv6 address and prefix. Full expansion, network address, first/last host, address type classification, and visual group breakdown showing network vs host bits.
Comparison
Config Diff Tool
Paste before and after configs. See exactly what changed — added, removed, modified. Context-aware with ignore options. Essential for maintenance window reviews.
Encoder
Base64 & Encoder
Encode and decode Base64, Hex, URL, and HTML. Hash text with SHA-256, SHA-1, and MD5. All local — nothing sent anywhere.
Tester
Regex Tester
Live regex pattern matching with highlighted results. Presets for network automation — IP extraction, BGP state, interface names, Netmiko output parsing.
Photography
Field of View Calculator
Enter focal length and sensor size. Get horizontal, vertical, and diagonal angles of view, crop factor, and equivalent focal lengths across all sensor formats including DJI drones.
Email
MX Lookup
Query MX records for any domain. See mail server hostnames, priority order, resolved IPs, and identify the email provider (Google, Microsoft, Proofpoint, etc.).
Email
SPF Checker
Fetch and parse SPF TXT records. Every mechanism explained in plain English — include, ip4, mx, all. Policy scored with actionable findings.
Email
DMARC Checker
Fetch and parse DMARC records. Every tag explained (p, rua, ruf, pct, adkim, aspf). Policy scored from none → quarantine → reject.
Email
DKIM Checker
Look up DKIM public key records by domain and selector. Common selectors preloaded for Google, Microsoft, Mailchimp, SendGrid, Fastmail, and more.
Email
Email Blacklist Checker
Check any IP against 25+ major email blacklists (DNSBLs) — Spamhaus ZEN, Barracuda, SORBS, SpamCop and more. See results in real time as each list is checked.
Email
Email Header Analyzer
Paste raw email headers. Get parsed delivery path, SPF/DKIM/DMARC results, hop-by-hop timing, TLS status, and spam scores. 100% local.
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More tools coming
Python NetOps snippets, LLM prompt library, cheatsheets. If you have a request, get in touch.