From f8a21f2552b32326070cb142e7c07303c0cc8b10 Mon Sep 17 00:00:00 2001 From: Jet Hughes Date: Mon, 3 Apr 2023 10:46:22 +1200 Subject: [PATCH] vault backup: 2023-04-03 10:46:22 --- content/notes/11-DNS.md | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/content/notes/11-DNS.md b/content/notes/11-DNS.md index 770bb311c..95b7bd25e 100644 --- a/content/notes/11-DNS.md +++ b/content/notes/11-DNS.md @@ -27,6 +27,8 @@ tags: > then sub domains ⇒ `google.com`, `ocss.nz` > and sub sub ⇒ `otago.ac.nz` > the advatage of tree structure is that the parent only need to know the domain name of the sub domains and the name server +> internal nodes are "zones" +> a "domain" is a leaf node. > [!INFO] google.com -> otago.ac.nz > first find nameserver for `.nz` if they already know the address for `.nz` then can go directly @@ -46,11 +48,37 @@ tags: > [!INFO] DNS vs NIS > dns is centralised, NIS is local +> [!INFO] BIND +> windows -> WIND +> software to implement a DNS server +> "**BIND (Berkeley Internet Name Domain) is a software collection of tools including the world's most widely used DNS (Domain Name System) server software**. This feature-full implementation of DNS service and tools aims to be 100% standards-compliant and is; intended to serve as a reference architecture for DNS software." + > [!INFO] Queries > iterative query - doesn't give you the final answer only gives the name of the next server > recursive query - only send the recurive query to final server. this must return the data requested for tell you that it doesn't exist. > a LAN with an NIS will return recursive queries for all subdomain with that LAN +> [!INFO] Files +> /etc/nsswitch +> /etc/hosts → contains local names, you can hardcode mappings in this file. this is more secure. if a domain name server if compromised you dont get the wrong name +> /etc/resolv.conf → should put address here? +> /etc/named.conf → root of the conf file. recruits other conf files. contains foward and reverse mappings +> /etc/named.root → contain the names and other information of root servers +> need to configure resolve order files->DNS + +> [!INFO] resource record +> when you contact nameserver you need to put resource record there? +> all names is record automaticall append parent domain name +> e.g., server1 becomes server1.otago.ac.nz +> resource records have different types +> this allow sthe BIND to know which is which + +> [!INFO] types of server +> primary - one which most of the time is working +> secondary - backup +> we need high reliability, they can communicate between each other to update changes + + Problem - How to get the IP address with an IP name? - Mapping between IP addresses and IP names