1. DNS and Bind
Presenter
David Wood

2. DNS What is DNS and Why do we care DNS history Client side stuff
Problems with DNS
Why Bind and what other options
Some key words for DNS
BIND Files
Named.conf
Db files
Conclusion

3. What is DNS and Why do we care
Domain Name Service
Hostnames and IP addresses
->
13 Root dns servers world wide

4. DNS History DNS was first made in 1982 Arpanet made DNS
DNS in the Enterprise

5. Client Side Stuff /etc/resolv.conf Domain example.com
Search example.com
Nameserver prefer
Nslookup
Dig
Dig -t MX gmail.com

6. Problems with DNS
Round Robin
DNS Outage
Master outage
DNS Redundancy

7. Why Bind and what other types
Bind is the leading DNS server across the world
9 out of 13 Root servers prefer Bind
Features of Bind
Tsig
Views
Other DNS versions
Microsoft
Lbnamed
Ldap
nis

8. Types of DNS
Caching-only
Forward
Master
Slave

9. Some key words for DNS Record types A Www.google.com Is where? CNAME
Isnt the real name?
PTR
I know the IP but whats the hostname MX
Mail servers NS
Other DNS servers

10. Bind files to know
/etc/named/named.conf
/var/named/db.*

11. Named.conf options { directory "/var/named"; version "get lost";
allow-transfer {"none";};
allow-recursion { /24;}; };
logging{
channel example_log{
file "/var/log/named/example.log" versions 3 size 2m;
severity info;
print-severity yes;
print-time yes;
print-category yes;
category default{
example_log;

12. Named.conf cont. // required zone for recursive queries zone "." {
type hint;
file "root.servers";};
zone "example.com" in{
type master;
file "master/db.master.example.com";
Allow-transfer { ; ;); };
zone "localhost" in{
file "master.localhost";
allow-update{none;}; };
zone " IN-ADDR.ARPA" in{
file "db rev"; };

13. db.example.com example
$TTL ; 24 hours could have been written as 24h or 1d
$ORIGIN example.com.
@ 1D IN SOA ns1.example.com. hostmaster.example.com. (
; serial
3H ; refresh
15 ; retry
1w ; expire
3h ; minimum )
IN NS ns1.example.com. ; in the domain
IN MX 10 mail.another.com. ; external mail provider
ns1 IN A ;name server definition
www IN A ;web server definition
ftp IN CNAME ;ftp server definition
www IN A
fred IN A

14. Conclusion Running DNS at home Running DNS for your own website
Running DNS at work

15. If there is time - Security
Split-zone DNS
Views
Chroot
Dont run as root
Flags for named
-t – chroot the service
-u – Run as a different user
-c – location to config file within chroot environment