Net

Check IP addresses and CIDR ranges: whether an address is valid, private, or inside a range.

Reference

Functions

cidrContains

cidrContains reports whether an IP address falls within a CIDR block. Returns false for malformed input rather than an error.

{{ cidrContains "10.0.0.0/8" "10.4.2.7" }}  → true

ipIsPrivate

ipIsPrivate reports whether an IP address falls within a private (RFC 1918 / RFC 4193) range. Covers 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, and fc00::/7.

{{ ipIsPrivate "192.168.1.20" }}  → true

ipValid

ipValid reports whether a string is a valid IPv4 or IPv6 address.

{{ ipValid "10.4.2.7" }}  → true
{{ ipValid "10.4.2" }}    → false