[dependencies]
trust-dns-resolver = "0.11.0"
trust-dns = "0.16.0"Copy

use std::env;
use trust_dns_resolver::Resolver;
use trust_dns_resolver::config::*;
use trust_dns::rr::record_type::RecordType;

fn main() {
    let args: Vec<String> = env::args().collect();
    if args.len() != 2 {
        eprintln!("Please provide a name to query");
        std::process::exit(1);
    }
    let query = format!("{}.", args[1]);

    // 创建默认解析器
    println!("Using the synchronous resolver");
    let resolver = Resolver::new(ResolverConfig::default(), ResolverOpts::default()).unwrap();
    let response = resolver.lookup_ip(query.as_str());
    for ans in response.iter() {
        println!("{:?}", ans);
    }

    // 根据系统配置文件创建解析器，linux下为从/etc/resolv.conf创建
    println!("Using the system resolver");
    let system_resolver = Resolver::from_system_conf().unwrap();
    let system_response = system_resolver.lookup_ip(query.as_str());
    for ans in system_response.iter() {
        println!("{:?}", ans);
    }

    println!("NS records using the synchronous resolver");
    let ns = resolver.lookup(query.as_str(), RecordType::NS);
    for ans in ns.iter() {
        println!("{:?}", ans);
    }
}Copy

cargo run baidu.com//注意，不要用www.baidu.com，否则会查询不到Copy