
                            <<DNS Balance>>

 By: YOKOTA Hiroshi <yokota@netlab.is.tsukuba.ac.jp>


[1. What's this]

 DNS Balance is a load-balancing DNS server.
Today's Web server, like "kernel.org", "*bsd.org" and Ring Server Project
(http://www.ring.gr.jp/) are mirrored all over the world. DNS Balance
selects fast server from all over the world for DNS resolver.

 DNS Balance has these functions:

o Dynamic load balancing.
o Answer different IP address between DNS client's IP address.
o Minimun implement. This may be good for security.


[2. What you need]

 DNS Balance requires Ruby (http://www.ruby-lang.org/).
So, you must install it. Some PC-UNIX has binary packages.


[3. What you do]

1. Extract the archive in "/usr/local/share". If you want to extract another
   directory, change "$prefix" in script "dns_balance.rb".
2. File "addrdb.rb" is the address database. You must edit this for
   your site.

------------------
$addr_db = {
  "130.12.0.0/16" => {         # => Request from 130.12.0.0/16
                               #    For example, DNS client's IP is
                               #    "123.45.67.89", search "123.45.67.89/32" to
                               #    "0.0.0.0/1".
    "www.foo.com" => [         # => IP address for "www.foo.com"
                               #    This host name must be lower case character.
      [[1,2,3,4], 0],          # => IP address and badness information.
      [[1,2,3,5], 10000],      #    Badness must be 0-10000. 0 is for fastest
      [[1,2,3,6], 9000],       #    server, and 10000 is for downed server.
      [[1,2,3,7], 9000],
    ],
  },
  "default" => {               # => If theres nothing to match, use "default".
    "www.foo.com" => [
      [[1,2,3,4], 0],
      [[1,2,3,5], 100],
      [[1,2,3,6], 1000],
      [[1,2,3,7], 9000],
    ],
    "localhost" => [
      [[127,0,0,1], 0],
    ],
  },
}
------------------

3. If your addrdb.rb is too complex to maintain, you can use namespace.rb .

------------------
$namespace_db = {
  "127.0.0.0/8"     => "localnet", # Write IP address and its alias name.
  "192.168.0.0/16"  => "foo-net",  # If client IP is 123.45.67.89, search
  "130.199.0.0/16"  => "foo-net",  # "123.45.67.89/32" to "0.0.0.0/1".
  "130.123.12.0/28" => "foo-net",
}
------------------

   If you use namespace.rb , you can write this way.

------------------
$addr_db = {
  "localnet" => {
    "www.foo.com" => [
      [[1,2,3,6], 2000],
      [[1,2,3,7], 1000],
    ],
  },
  "foo-net" => {
    "www.foo.com" => [
      [[1,2,3,4], 0],
      [[1,2,3,5], 100],
    ],
  },
  "default" => {
    "www.foo.com" => [
      [[1,2,3,4], 0],
      [[1,2,3,5], 10000],
      [[1,2,3,6], 9000],
      [[1,2,3,7], 9000],
    ],
  },
}
------------------

4. You can use "--as" option to use "Autonomous System" information
   from whois.ra.net .

   whois.ra.net offers AS information.
---------
$ whois -h whois.ra.net 192.168.0.1
route:         192.168.0.0/24
descr:         Foo networks
origin:        AS1000   <==================== This is AS information
member-of:     RS-COMM_FOONET
mnt-by:        MAINT-AS1000
changed:       rm@foo.ad.jp 99999999
source:        BARNET
---------

   You can use AS information like this.

--------------
$addr_db = {
  "AS1000" => {
    "www.foo.com" => [
      [[1,2,3,4], 0],
    ],
  },
  "default" => {
    "www.foo.com" => [
      [[1,2,3,4], 0],
      [[1,2,3,5], 10000],
    ],
  },
}
--------------


5. Run DNS Balance. Type "ruby /usr/local/lib/DNS-Balance-x.x/dns_balance.rb"
   for run DNS Balance.

6. If exists a file named "addr", DNS Balance is loads automatically every
   5 minutes. This file contains same database as "addrdb.rb".
   I make some sample script like CSV -> address database converter.
   See "sample" directory

7. "-i xxx.xxx.xxx.xxx" to specify listen IP address.
   And "-h" to display some help message.


[4. Copyright]

 See README.dns_balance.

 If you want newer version, see my homepage.
   URL http://www.netlab.is.tsukuba.ac.jp/~yokota/
       http://www.netlab.is.tsukuba.ac.jp/~yokota/izumi/dns_balance/

 Any questions and suggestions are welcome.

                  2002/09/06: YOKOTA Hiroshi (yokota@netlab.is.tsukuba.ac.jp)