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0 : DNS/WHOIS
1 : Before going to today's topic...
2 : Therefore,
3 : Let's find HUB and Router (1)
4 : Let's find HUB and Router (2)
5 : Let's find HUB and Router (3)
6 : Let's find HUB and Router (4)
7 : Let's find HUB and Router (5)
8 : Let's find HUB and Router (6)
9 : Other late questions
10 : Miscellaneous
11 : Miscellaneous
12 : DNS/WHOIS
13 : DNS
14 : host/dig commands
15 : How your DNS works
16 : Root Servers
17 : Reverse Lookup
18 : Type of Records
19 : MX
20 : CNAME
21 : SOA
22 : Distributed Database
23 : Tools
24 : Whois
25 : Quiz of the day
26 : Homework
DNS/WHOIS
Tokio Kikuchi
Before going to today's topic...
There were many who don't know HUB and Router.
:-<
HUB
Extends
a
network
Router
Connects
two
or more networks
Therefore,
HUB is related to
Ethernet
Router is related to
Internet
Let's find HUB and Router (1)
Let's find HUB and Router (2)
Let's find HUB and Router (3)
Let's find HUB and Router (4)
Let's find HUB and Router (5)
Let's find HUB and Router (6)
Other late questions
what are the commands for getting IP/MAC address etc
ifconfig -a
... for IP/MAC
netstat -r
... for (default) routers
arp -a
... for IP/MACs on your network
Miscellaneous
Loopback interface
Your own host ... localhost
IP address = 127.0.0.1
Worlds worst hacker
(Joke)
Miscellaneous
Private address ... no use for global routing
10.0.0.0 -- 10.255.255.255
172.16.0.0 -- 172.31.255.255
192.168.0.0 - 192.168.255.255
DNS/WHOIS
IP address to/from host name mapping
who owns this IP/domain ?
DNS
Domain Name System
Specify DNS Server (DHCP or manually)
Ask your DNS by (ip/hostname)
Your DNS returns (hostname/ip)
host/dig commands
Read the manual and try.
dig
returns more elaborated answers
How your DNS works
Ask
.
DNS server for www.kochi-u.ac.jp
.
returns
jp
DNS server
Ask
jp
DNS server for www.kochi-u.ac.jp
jp
returns
kochi-u.ac.jp
DNS server
Ask
kochi-u.ac.jp
DNS server for www.kochi-u.ac.jp
kochi-u.ac.jp
returns ip address of www.kochi-u.ac.jp
Root Servers
serves for
.
domain
a.root-servers.net ... m.root-servers.net
How to find root servers
Reverse Lookup
www.kochi-u.ac.jp >>> . -> jp -> ac -> kochi-u -> www -> 133.97.2.55
133.97.2.55 -> ?
55.2.97.133.in-addr.arpa >>> . -> in-addr.arpa -> 133 -> 97 -> 2 -> 55
Type of Records
A ... IPv4 address
PTR ... Pointer (Reverse Look-up)
AAAA ... IPv6 address
Others follow ...
MX
mail exchange
Gateway to other mail system (UUCP/X.500/mobile)
CNAME
Canonical Name
alias => canonical name
SOA
Start of Authority
Whats in there?
Distributed Database
DNS is a
highly coordinated
distributed database
many
rules
DNS related RFCs
Tools
host, dig, nslookup
Python
socket.gethostbyname()
socket.gethostbyaddr()
Whois
Another DB for Internet Information
who owns this IP/domain ?
RFC954
subquery is implemented in whois command
depends on implementation
whois -h whois.nic.ad.jp TK197JP
Quiz of the day
What command do you use if you want to ...
know the IP address of www.whitehouse.gov ?
know who is attacking my server ? I know his IP address.
Homework
Collect information of your mail domain using DNS and Whois.
Your mail domain
is outside of kochi-u.ac.jp.
If you don't have other email address, then try kochi-u.ac.jp.