Docker Network Overlap Checker
Check candidate or existing Docker subnets against your VPN, office LAN, and other reserved ranges for overlaps.
This tool handles input and primary processing in your browser and is designed not to send the input to QuickKit’s server.
How it works
This computes address arithmetic only — it does not talk to a Docker daemon, read your routing table, or know what is actually running. Paste your candidate or existing Docker subnets (optionally "name CIDR" per line, or a bare CIDR) and the ranges you want to protect (host routes, VPN, corporate LAN). Every Docker entry is compared against every reserved entry using exact CIDR containment and intersection math, and against every other Docker entry for exact duplicates. Only the leading address/CIDR token of each reserved line is read, so pasted "ip route" output works directly — a "default via …" line is skipped rather than treated as an entry.