From 1d00269da457556def4cf169fe0c190696ad62d3 Mon Sep 17 00:00:00 2001 From: Brendan Golden Date: Sat, 14 Oct 2023 17:13:43 +0100 Subject: [PATCH] slide: added a slide on DNS --- src/slides/skynet/4_dns.md | 119 +++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) create mode 100644 src/slides/skynet/4_dns.md diff --git a/src/slides/skynet/4_dns.md b/src/slides/skynet/4_dns.md new file mode 100644 index 0000000..273df74 --- /dev/null +++ b/src/slides/skynet/4_dns.md @@ -0,0 +1,119 @@ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +title = "Skynet: DNS" +date = 2023-10-14 +slides = true ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ + + +# DNS + +------------------------------------------------------------------------- + +## Overview + +------------------------------------------------------------------------- + +DNS is both simple and complex. + +------------------------------------------------------------------------- + +DNS translates the human domains into something computers can understand. + +------------------------------------------------------------------------- + +```dns +skynet IN A 193.1.96.165 +*.users IN CNAME skynet +``` + +------------------------------------------------------------------------- + +It can also provide useful information. + +------------------------------------------------------------------------- + +```dns +skynet.ie. IN TXT "v=spf1 a:mail.skynet.ie -all" +``` + +------------------------------------------------------------------------- + +## Structure + +------------------------------------------------------------------------- + +DNS is hierarchical and delegated. + +------------------------------------------------------------------------- + +Root servers + +------------------------------------------------------------------------- + +TLD (Top Level Domain) servers (``.ie``, ``.com``, ``.eu``) + +------------------------------------------------------------------------- + +Domain servers (``skynet.ie``) + +------------------------------------------------------------------------- + +We run our own DNS servers, Bind9 (``ns1.skynet.ie``, ``ns2.skynet.ie``) + +------------------------------------------------------------------------- + +We also have control over ``csn.ul.ie`` and ``ulcompsoc.ie`` + +------------------------------------------------------------------------- + +## Viewing DNS records + +------------------------------------------------------------------------- + +On the nixos repo: +```bash +colmena build --keep-result --on vendetta +cat .gcroots/node-vendetta/etc/skynet/dns/skynet.ie +``` + +------------------------------------------------------------------------- + +On top of that we also manage the reverse DNS (rDNS) + +------------------------------------------------------------------------- + +Reverse DNS allows you to look up and IP and get the domains. + +------------------------------------------------------------------------- + +```bash +cat .gcroots/node-vendetta/etc/skynet/dns/64-64.99.1.193.in-addr.arpa +``` + +------------------------------------------------------------------------- + +To validate them there is this tool: <> +(put ``skynet.ie`` in teh FQDN box) + +------------------------------------------------------------------------- + +## Commands + +------------------------------------------------------------------------- + +```bash +dig skynet.ie +dig skynet.ie @1.1.1.1 +dig skynet.ie @ns1.skynet.ie +host 193.1.99.75 +``` + +------------------------------------------------------------------------- + +//Use this time to explore the nixos repo to explain// + +------------------------------------------------------------------------- + +* <> +* <> +