From 16c4b4d6f6bb2095b9625fb0c7022d4a55888165 Mon Sep 17 00:00:00 2001 From: Jet Hughes Date: Mon, 3 Apr 2023 10:31:22 +1200 Subject: [PATCH] vault backup: 2023-04-03 10:31:22 --- content/notes/11-DNS.md | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) diff --git a/content/notes/11-DNS.md b/content/notes/11-DNS.md index a9dbd2245..770bb311c 100644 --- a/content/notes/11-DNS.md +++ b/content/notes/11-DNS.md @@ -19,7 +19,37 @@ tags: > [!INFO] distributed dns > now dns is distributed. it is a BIND (berkely internet name domain) service. -> to do something distributedly. each LAN has their own DNS +> to do something distributedly. each LAN has their own NIS. each LAN manages their own domain names and IP addresses. +> LANs can talk between each other. +> we use a tree structure for domain names +> at the start we have a root domain ⇒ `.` +> then we have domains ⇒ `.com`, `.nz`, `.org` +> 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 + +> [!INFO] google.com -> otago.ac.nz +> first find nameserver for `.nz` if they already know the address for `.nz` then can go directly +> otherwise they need to go through the root name server `.` +> you should configure this root Domain name server on a new installation +> the root name server send the address of the `.nz` name server which sends the address of the `.ac.nz` name server, and so on until you get the final address + +> [!INFO] nameserver storage +> some nameservers such as `.nz` are held by IANA + +> [!DEFINITION] NIS +> network information system + +> [!DEFINITION] DNS +> domain name service + +> [!INFO] DNS vs NIS +> dns is centralised, NIS is local + +> [!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 Problem - How to get the IP address with an IP name?