Network tools
Subnets, DNS, IPs: the daily bread of network admins, done right.
IPv4 Subnet Calculator
CIDR, masks, ranges and subnet splitting with a visual map of the address space.
Runs in your browser
DNS Lookup
A, AAAA, MX, TXT, NS, CNAME and more, with response times and copy-ready records.
Reading in this category
What is a /24? CIDR notation and subnet masks, finally clear
A /24 is a block of 256 IPv4 addresses, 254 usable. What the slash number means, how masks work bit by bit, and how to size real networks.
What is DNS TTL? Cache, propagation and the values to use
TTL is the number of seconds resolvers may cache a DNS answer. How it really works, why propagation is mostly waiting, and the right TTL per situation.