SPARCS 1

DNS Domain Name System

SPARCS `08 서우석 (pipoket)

`09 Summer Wheel Seminar

2009-07-21

SPARCS 2

▶ TCP/IP

2009-07-21

143.248.246.144

SPARCS 3

▶ Think about this

202.131.29.7074.125.67.100

203.226.253.11211.115.77.211

143.248.234.102

Can you remember all?

2009-07-21

SPARCS 4

▶ Domain Name

MAP IP with “Domain”

2009-07-21

143.248.246.144

sparcs44.kaist.ac.kr

SPARCS 5

▶ Think about this, again

202.131.29.70 = www.naver.com74.125.67.100 = www.google.com203.226.253.11 = www.nate.com211.115.77.211 = www.daum.net143.248.234.102 = sparcs.kaist.ac.kr

2009-07-21

SPARCS 6

▶ But How?

2009-07-21

I don’t know!

Zzzzz….

Please download this!

Oh, that`s 202.131.29.70

www.naver.com ?

202.131.29.70 !

SPARCS 7

▶ What about this?

2009-07-21

www.naver.com ?

I said, I DON`T KNOW!

ZZZZZzzz….

Anyway download it!

Oh, kill me

SPARCS 8

▶ Server is also Computer

Die, Hang, Stop, Busy, Powered off

Then,Why don`t we “Distribute” it?

2009-07-21

SPARCS 9

▶ Let`s Distribute!

2009-07-21

www.naver.com ?

I think 202.131.29.70

That`s 110.76.24.34!

I swear that naver domain is gone

What the f…..?

Simple! 234.222.1.4

SPARCS 10

▶ What do we need?

We need

Protocol(Agreement)

2009-07-21

SPARCS 11

▶ Domain Name Server

2009-07-21

Oh, that`s 202.131.29.70

www.naver.com ?

DNS

SPARCS 12

▶ Protocol #1 – How to request

2009-07-21

????????

What`s the IP of www.naver.com ?

¿ Qué es el IP dewww.naver.com ?

SPARCS 13

▶ Protocol #1 – How to request

Port : UDP 53Format :

2009-07-21

Oh, that`s 202.131.29.70

www.naver.com ?

;www.naver.com. IN A

SPARCS 14

▶ Protocol #2 – How to distribute

2009-07-21

www.naver.com ?

DNS02, Do you know?

DNS03, Do you know?

DNS01, Do you Know?

……?

DNS02, Do you know?

DNS03, Do you know?

DNS01, Do you Know?

SPARCS 15

▶ Protocol #2 – How to distribute

2009-07-21

sparcs . kaist . ac . krkr

ac

kaist

sparcs

mail

www

korea

co go

seoul

www

mail

dae-jeon

www

mail

pe

SPARCS 16

▶ Protocol #2 – How to distribute

2009-07-21

Top level : kr, com, gov, milSecond Level : co, pe, neThird Level(hostname) : kaist, google*Fourth level : Anything!

Distribution by Hierarchy

SPARCS 17

▶ Protocol #2 – How to distribute

2009-07-21

From : mail.seoul.go.krRequest : sparcs.kaist.ac.kr kr

ac

kaist

sparcs

mail

www

korea

co go

seoul

www

mail

dae-jeon

www

mail

pe

1. seoul? Do you know?

2. go? Do you know?

3. kr? Do you know?

4. Ask ac, 110.42.3.1

5. I think kaist knows that

6. sparcs = 143.248.246.102

7. 143.248.246.102!

SPARCS 18

▶ Protocol #3 – Update

We need Update!

2009-07-21

a.com = 164.240.4.23

Gosh! I`ll update a.com

I Thought thata.com doesn`t ex-

ist!

I already know that

SPARCS 19

▶ Protocol #3 – Update

2009-07-21

kr

ac

kaist

sparcs

mail

www

korea

co go

seoul

www

mail

photo

dae-jeon

www

mail

pe

SPARCS 20

▶ Protocol #3 – Update

2009-07-21

kr

ac

kaist

sparcs

mail

www

koryuh

co go

seoul

www

mail

dae-jeon

www

mail

pe

Oh.. korea -> koryuh

korea -> koryuh?!

SPARCS 21

▶ Protocol #3 – Update

2009-07-21

Periodically Update : Cache Time

So It takes some time when you Update, Buy, Setup

Your Domain.

SPARCS 22

▶ Protocol #4 – How to Manage

2009-07-21

AuthorityZone

SPARCS 23

▶ Protocol #4 – How to Manage

2009-07-21

Take a Look at sparcs.orgnan.sparcs.orgmir.sparcs.orgbit.sparcs.orgksearch.sparcs.org

Authority Server

Zone

SPARCS 24

▶ We`ve got a clue!

We now know protocols!

But…How can we set it up?

Program helps us to follow “Protocol”?

How can we make own PC as DNS?

2009-07-21

SPARCS 25

▶ Next seminar

bind9You will learn many more things!

Making Authority Server,Setting Zone, SOA, TTL…

2009-07-21

SPARCS 26

▶ Appendix – Interesting Story

What if “kr” DNS server

goes DOWN?

From: mail.seoul.go.krRequest: www.kaist.ac.kr

2009-07-21

SPARCS 27

▶ 2003.01.25

2009-07-21

혜화전화국 DNS

Biggest DNS(Uppermost)

in Korea

SPARCS 28

▶ Why?

DDOS“Distribute Denial Of Service” attack

2009-07-21

SPARCS 29

▶ Familiar?

2009-07-21

It`sHappening

AGAIN

SPARCS 30

▶ To SPARCS pre-wheel

Be informed!Search about recent Security Is-

sue!Have some interest about it!

Information is Power!

2009-07-21