DNS

After looking on Ubuntu forum for an easy step-by-step howto for instaling a DNS server, I decided the best idea would probably be to write this howto myself.... So, here it is!

Step 1: Install Ubuntu dapper, or use your WORKING installation.

Step2: Install bind 9:

sudo apt-get install bind9

Step 3: Configure the main Bind files. Usually, if you install Bind from the source code, you will have to edit the file named.conf. However, Ubuntu provides you with a pre-configured Bind, so we will edit another file:

sudo vi /etc/bind/named.conf.local

This is where we will insert our zones. By the way, a zone is a domain name that is referenced in the DNS server Insert this in the named.conf.local file:

# This is the zone definition. replace example.com with your domain name
zone "example.com" {
       type master;
       file "/etc/bind/zones/example.com.db";
       };

# This is the zone definition for reverse DNS. replace 0.168.192 with your network address in reverse notation - e.g my network address is 192.168.0
zone "0.168.192.in-addr.arpa" {
     type master;
     file "/etc/bind/zones/rev.0.168.192.in-addr.arpa";
};

Ok, now, let's edit the options file:

sudo vi /etc/bind/named.conf.options

We need to modify the forwarder. This is the DNS server to which your own DNS will forward the requests he cannot process.

forwarders {
     # Replace the address below with the address of your provider's DNS server
     123.123.123.123;
};

Now, let's add the zone definition files (replace example.com with your domain name:

sudo mkdir /etc/bind/zones
sudo vi /etc/bind/zones/example.com.db

The zone definition file is where we will put all the addresses / machine names that our DNS server will know. You can take the following example:

// replace example.com with your domain name. do not forget the . after the domain name!
// Also, replace ns1 with the name of your DNS server
example.com.      IN      SOA     ns1.example.com. admin.example.com. (
// Do not modify the following lines!
                                                       2006081401
                                                       28800
                                                       3600
                                                       604800
                                                       38400
)

// Replace the following line as necessary: // ns1 = DNS Server name // mta = mail server name // example.com = domain name example.com. IN NS ns1.example.com. example.com. IN MX 10 mta.example.com.

// Replace the IP address with the right IP addresses. www IN A 192.168.0.2 mta IN A 192.168.0.3 ns1 IN A 192.168.0.1

Now, let's create the reverse DNS zone file:

sudo vi /etc/bind/zones/rev.0.168.192.in-addr.arpa

Copy and paste the following text, modify as needed:

//replace example.com with yoour domain name, ns1 with your DNS server name.
// The number before IN PTR example.com is the machine address of the DNS server. in my case, it's 1, as my IP address is 192.168.0.1.
@ IN SOA ns1.example.com. admin.example.com. (
                       2006081401;
                       28800; 
                       604800;
                       604800;
                       86400 
)
                     IN    NS     ns1.example.com.
1                    IN    PTR    example.com

Ok, now you just need to restart bind:

sudo /etc/init.d/bind9 restart

We can now test the new DNS server... Step 4: Modify the file resolv.conf with the following settings:

sudo vi /etc/resolv.conf

enter the following:

// replace example.com with your domain name, and 192.168.0.1 with the address of your new DNS server.
search example.com
nameserver 192.168.0.1

Now, test your DNS:

dig example.com

Look at the result.... Enjoy!
Also, this post is not perfect... Do not hesitate to improve it!

http://ubuntuforums.org/showthread.php?t=236093

ещё статьи: http://www.linuxcenter.ru/lib/articles/networking/bind9_dnscache.phtml

Патч для уязвимости DoS через запросы подтверждения DNSSEC в ISC BIND
http://safe.cnews.ru/bugtrack/entry/index.shtml?patch/2007/06/19/100467