All nameservers in one subnet
Check id: ns.all_same_subnet · fix effort: medium
What it means
All your DNS servers live in the same small network segment. One outage takes them down together.
The technical detail
All NS IPv4 addresses fall within one /24. RFC 2182 recommends topological diversity.
How to fix it
- Use a DNS provider with anycast or geographically separate nameservers.
Does your domain have this problem?
Run a free scan, takes about ten seconds.