DNS & CIDR
Look up DNS records over DNS-over-HTTPS and calculate IPv4 CIDR subnet ranges.
About this tool
DNS mode queries A, AAAA, CNAME, MX, TXT, NS, and CAA records for a domain — directly from your browser via DNS-over-HTTPS to Cloudflare (1.1.1.1) or Google (8.8.8.8). It is handy for checking domain setup, certificate issuance prerequisites (CAA), and email configuration (MX, SPF in TXT).
CIDR mode breaks an IPv4 block like 10.0.0.0/16 into its network address, broadcast address, netmask, and usable host range, and can check whether a specific IP falls inside the block — useful for VPC design and security group debugging.
Frequently asked questions
Why do results differ from dig or my local resolver?+
DNS answers are cached by TTL at every resolver. Cloudflare and Google may hold different cache states than your ISP. Switching the resolver here is a quick way to spot propagation in progress.
How long does DNS propagation take?+
Until the old record's TTL expires at each resolver — typically minutes to hours. Lower the TTL in advance if you plan a cutover.
What does the /24 in 10.0.1.0/24 mean?+
The prefix length: how many leading bits are fixed as the network part. /24 fixes 24 bits, leaving 8 bits → 256 addresses, 254 usable hosts.
Why are 2 addresses subtracted from usable hosts?+
The first address is the network identifier and the last is the broadcast address. Exceptions: /31 (point-to-point links) and /32 (single host) use every address.