CIDR Calc

Networking tools

Practical troubleshooting and planning tools that complement CIDR Calc.

Back to toolsCIDR Calc

Packet Path Triage

A fast, ordered checklist to diagnose connectivity issues.

Subnet Collision Scanner

Paste CIDRs and detect overlaps in seconds.

Route Summarizer

Summarize routes into the smallest supernets.

ACL Builder

Generate ACL lines with wildcard masks and ports.

VLSM Planner

Allocate subnets based on host requirements.

NAT Detector

Identify NAT type and likely failure points.

MTU Finder

Step-by-step PMTUD checks and recommended MTUs.

DNS Triage

Troubleshoot resolution issues in the right order.