whoizz

A tiny, dependency-light RFC 3912 whois client for Rust. Supports both domain whois (via TLD registries) and IP whois (via the Regional Internet Registries — ARIN, RIPE, APNIC, LACNIC, AFRINIC). Queries IANA for the authoritative server, follows the refer: line, and returns both the raw response and a best-effort extraction of the common fields (registrar, creation/expiry dates, name servers).

No async runtime, no custom protocol crates — just std::net::TcpStream and thiserror.

Usage

Domain lookup

use whoizz::lookup;

fn main() -> Result<(), whoizz::WhoisError> {
    let r = lookup("rust-lang.org")?;
    println!("registrar:   {:?}", r.registrar);
    println!("created:     {:?}", r.created);
    println!("expires:     {:?}", r.expires);
    println!("nameservers: {:?}", r.nameservers);
    println!("--- raw ---\n{}", r.raw);
    Ok(())
}

IP lookup

use std::net::IpAddr;
use whoizz::lookup_ip;

fn main() -> Result<(), whoizz::WhoisError> {
    let ip: IpAddr = "8.8.8.8".parse().unwrap();
    let r = lookup_ip(ip)?;
    println!("server: {}", r.server);      // e.g. "whois.arin.net"
    println!("raw:\n{}", r.raw);
    Ok(())
}

What it does

1. Extracts the TLD from the input domain.
2. Queries whois.iana.org to discover the authoritative whois server for that TLD (the refer: line in the IANA response).
3. Opens a TCP connection to the referred server on port 43, sends <domain>\r\n, reads the response until EOF.
4. Parses the free-text response heuristically to extract the common fields. Whois responses are not standardized across registries, so field extraction is best-effort — the raw field always contains the full response if you need to parse more yourself.

Limitations

• Best-effort parsing. Registrars format their responses however they like. If a field is missing or formatted oddly, it won't be extracted. The raw response is always available.
• Blocking I/O only. If you need async, wrap the call in tokio::task::spawn_blocking or equivalent.
• Rate limits apply. Most whois servers rate-limit queries per IP. Don't hammer them.
• Private / reserved IP ranges (RFC 1918, CGNAT, loopback, etc.) return whichever response the RIR gives — usually a reservation notice rather than a registration record. Filter client-side if you only want public IPs.

License

MIT — see LICENSE.