DNS

Resource

Managing DNS Essential Training from lynda.com

DNSCrypt

• https://en.wikipedia.org/wiki/DNSCrypt
• dnscrypt-proxy 2 - A flexible DNS proxy, with support for encrypted DNS protocols
• Install and Enable DNSCrypt Proxy 2 in Ubuntu 18.04 Or 18.10 / Debian Unstable Or Testing

DNS server

• Introduction to the Domain Name System (DNS)
• Build your own DNS name server on Linux

setup

• https://support.rackspace.com/how-to/changing-dns-settings-on-linux/
• https://helix.nih.gov/user_guides/kerb5_config.html

DNSmasq (DNS + DHCP server)

• Man page and Setup
• Dnsmasq For Easy LAN Name Services
• https://wiki.archlinux.org/index.php/dnsmasq
• https://wiki.debian.org/HowTo/dnsmasq
• http://www.linuxjournal.com/content/dnsmasq-pint-sized-super-d%C3%A6mon
• https://blogging.dragon.org.uk/howto-setup-dnsmasq-as-dns-dhcp/

Local forwarding server

dnsmasq program is running on my Ubuntu and Linux/Mint machines.

See nameserver 127.0.1.1 in resolv.conf won't go away!

$ ps -ef | grep -i dnsmasq

$ sudo netstat -anp | grep -i dnsmasq

Change DNS setting

• Why Changing DNS Settings Increases Your Internet Speed, 5 DNS Servers Guaranteed to Improve Your Online Safety
  • https://1.1.1.1/, 隱私優先、速度最快，公共DNS服務1.1.1.1上線了
  • Google: 8.8.8.8 and 8.8.4.4
  • OpenDNS: 208.67.220.220 and 208.67.222.222
  • DNS Watch: 84.200.69.80 and 84.200.70.40
  • OpenNIC: 206.125.173.29 and 45.32.230.225
  • UncensoredDNS: 91.239.100.100 and 89.233.43.71
• Change DNS Settings on Windows / Mac / Android / IOS / Linux
• Setup CloudFlare DNS On Ubuntu 16.04 / 17.10 / 18.04 Desktop
  1. Open Ubuntu Network Manager (System settings > Network > Settings > Wired or Wireless or both)
  2. Select both IPv4 and IPv6 and turn off automatic DNS IP settings… then type the custom Cloudflare DNS IP addresses you want to use…
• You Can Now Use Cloudflare’s 1.1.1.1 DNS on Mobile

Flush DNS cache

How to clear the DNS Cache?

Test if you are using OpenDNS

https://welcome.opendns.com/

Query DNS server

To list the current DNS servers used by my system,

Method 1:

# Ubuntu >= 15
$ nmcli dev show | grep 'IP4.DNS'
$ nmcli device show <interfacename> | grep IP4.DNS
# Ubuntu <= 14
$ nmcli dev list iface <interfacename> | grep IP4

Method 2:

$ cat /etc/resolv.conf

Another way is to use the R packages: gdns and dnsflare. More Options For Querying DNS From R with 1.1.1.1.

3 Ways to Check DNS Propagation Status

https://www.makeuseof.com/tag/check-dns-propagation-status/