Skip to content

Name Server

A Name Server is a servers that resolve the DNS query (authoritative or non-authoritative)

  • Also known as:
  • public recursive name server
  • authoritative DNS server

  • recursive DNS resolver

  • A DNS server is any server that implements the DNS protocol

  • It manages dns tables centrally. Then all hosts must look up that server.
  • The host must configure the file /etc/resolv.conf with the dns server URL to fetch from
  • Add dns entries locally to /etc/hosts
search mycompany.com prod.mycompany.com # append domain names to the requests
nameserver 192.168.1.100 # ip of a dns server
nameserver 8.8.8.8 # another dns server (google)
  • DNS Lookup Order: 1st /etc/hosts, 2nd DNS server.

  • The order can be modified at /etc/nsswitch.conf (line with hosts entry)

  • Authoritative DNS Server

  • A DNS Server where the customer (you) can modify the DNS records
  • For instance, Route53 is both an authoritative DNS server and a domain registrar

DNS Server Types

Plain DNS

  • Plain UDP/53 connection

  • Public Servers

  • Google

    • 8.8.8.8 & 8.8.4.4 (unfiltered)

  • Cloudflare

    • 1.1.1.1 & 1.0.0.1 (unfiltered)
    • 1.1.1.2 e 1.0.0.2 (blocks malware)

  • AdGuard

DNS over HTTPS (DoH)

  • Establishes a TCP connection (instead of UDP) using TLS (encrypted) on port 443
  • Avoids DNS leak

  • Improvement: Oblivious DNS over HTTPS (ODoH)

  • Public Servers

  • AdGuard

DNS over TLS (DoT)

  • Plain TCP connection on port 853
  • Public Servers
  • AdGuard