Routing
Calculated locally
Longest Prefix Match Visualizer
Visualize matching routes and see exactly why the longest prefix wins for a destination IP.
Learn before you deploy
Reference PacketToolbox learning content related to this workflow.
Tool input
Use the fields below and run the calculation or generation locally.
Results
Review output and validation notes before production use.
How it works
Provide a destination and route list; the tool ranks all matching prefixes by specificity.
All processing runs in-browser with no external API dependency.
Practical example
Example: 10.10.10.42 prefers /27 over /24 and /16.
Related tools
Use these together for complete design and troubleshooting workflows.
- IPv4 Subnet Calculator for subnet boundary and wildcard checks.
- VLSM Planner for hierarchical IPv4 allocation.
- Route Summarization Calculator for clean route advertisement planning.
- Cisco ACL Builder for policy-generation workflows.