DNS

wikipedia:Domain Name System translates domain names to IP addresses. The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME).

A stands for Address AAAA are used for IPv6 addresses

Public DNS Servers

• Google: 8.8.8.8, 8.8.4.4
• Cloudflare: 1.1.1.1
• DigitalOcean Nameserver: ns1.digitalocean.com, ns2.digitalocean.com, and ns3.digitalocean.com

• Linux DNS

DNS servers

• Bind
• dnsmasq

Cloud

• Amazon Route 53

Client DNS utilities

Windows

• ipconfig /all
• nslookup

Linux:

• systemd-resolve: systemd-resolve --status
• dig
• host
• nslookup
• drill

macOS:

• scutil --dns
• dscacheutil -q host -a name example.com
  • sudo dscacheutil -flushcache;sudo killall -HUP mDNSResponder;
• dig
• nslookup
• networksetup -setdnsservers
• networksetup -setsearchdomains
• host

Activities

• Configure your DNS servers in Ubuntu. https://www.techrepublic.com/article/how-to-set-dns-nameservers-in-ubuntu-server-18-04/
• host -t ns DOMAIN_NAME.COM
• CKA v1.18: Know how to configure and use the cluster DNS

Related terms

• wikipedia:Pseudo-top-level domain
• nscd
• DNS recursion: recursion yes|no; in Bind
• Wildcard DNS records
• Resource records: MX, TXT, NS, AAAA, CNAME

See also

• Bind, /etc/bind/named.conf, rndc [status | reload ], named-checkconf
• DNS: Linux DNS, IP, systemd-resolve, /etc/hosts, whois, Domain registrar, dig, host, nslookup, scutil --dns dnsmasq, bind, delv, .local, .internal, .onion, FQDN, TTL, /etc/resolv.conf, /etc/systemd/resolved.conf, dscacheutil (macOS), hostname, hostnamectl, bind, resolvectl status, DNS sinkhole, Domain name server, LLMNR, Resource records:MX, TXT, NS, CAA, SSHFP, Apex, CNAME, Wildcard DNS records, Subdomain, /etc/nsswitch.conf, 1.1.1.1, 8.8.8.8, CoreDNS, dnsPolicy:, Google Public DNS, DNS caches, Kubernetes ExternalDNS, DNS forwarding, IDNA2008, DNS-1035, Domain name registrars, Split-view DNS, Pi-hole, NextDNS
• HTTP, HTTP client, HTTP/1.1, HTTP/2, HTTP/3, HTTPS, HSTS CSR, TLS, SSL, openSSL, WebSockets, WebRTC, ssl_certificate QUIC, HPKP, CT, List of HTTP status codes, URL redirection, Content-type:, Webhook, HTTP headers, --insecure, Axios HTTP client, HTTP cookies, HTTP ETag, Hypertext Transfer Protocol -- HTTP/1.1
• DHCP: Cisco IOS DHCP Server, isc-dhcp-server (dhcpd.conf), ip dhcp pool show ip dhcp pool, show ip dhcp binding, show ip dhcp conflict, show ip dhcp server statistics, DHCP snooping, client-identifier, hardware-address, show ip dhcp, ip link, dhcpcd, AWS::EC2::DHCPOptions, dhclient, systemd-networkd