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Anycast DNS

Description of service

This service provides an efficient and fault tolerant way of resolving 168.192.in-addr.arpa, 0.b.3.f.4.6.b.6.0.0.d.f.ip6.arpa and glanet.org zones across GLaNET.

Three levels of participation exist:

  • running a master DNS server: this server will be part of the DNS system ‘core’, thus it must be reachable, have a good connectivity and reliability (within GLaNET);
  • running a slave DNS server: if you have a large number of hosts in you network, you may want to run a slave DNS server to increase performances;
  • using your DNS server as a forwarder: this is a simplest way of using the service.
  • Anycast DNS IPv4: 192.168.248.53.
  • Anycast DNS IPv6: fd00:6b64:f3b0:53::1 (advertise fd00:6b64:f3b0:53::/64 over BGP).

List of anycast DNS servers

Host IPv4 IPv6 ASN
ns.fa0.org 87.98.182.144 2001:470:c8bc:2000::100 64542
ns0.lv0.in 91.121.93.194 2001:470:c8be::1 64544

Master configuration example

When adding a master server, don't forget that your DNS server must listen on 192.168.248.53 and/or fd00:6b64:f3b0:53::1, that your BGP router must advertise it and your firewall must not bock it.
Initial checkout: 
svn checkout https://svn.oxynux.org/glanet/dns/ /etc/bind/zones-glanet/

named.conf

zone "glanet.org" {
  type master;
  allow-transfer { any; };
  file "/etc/bind/zones-glanet/db.glanet.org";
};

zone "168.192.in-addr.arpa" {
  type master;
  allow-transfer { any; };
  file "/etc/bind/zones-glanet/db.192.168";
};

zone "0.b.3.f.4.6.b.6.0.0.d.f.ip6.arpa" {
  type master;
  allow-transfer { any; };
  file "/etc/bind/zones-glanet/db.fd00:6b64:f3b0";
};

crontab

*/5  *  * * * root  svn up /etc/bind/zones-glanet >> /dev/null && rndc reload >> /dev/null

FIXME Some zone checking should be done → SVN pre-commit

Slave configuration example

FIXME IPv6

named.conf

zone "glanet.org" {
  type slave;
  masters { 192.168.248.53; };
  file "/etc/bind/zones/db.glanet.org";
};

zone "168.192.in-addr.arpa" {
  type slave;
  masters { 192.168.248.53; };
  file "/etc/bind/zones/db.192.168";
};

zone "0.b.3.f.4.6.b.6.0.0.d.f.ip6.arpa" {
  type master;
  masters { 192.168.248.53; };
  file "/etc/bind/zones/db.fd00:6b64:f3b0";
};

Forwarder configuration example

FIXME IPv6

named.conf

zone "glanet.org" {
  type forward;
  forwarders { 192.168.248.53; };
};

zone "168.192.in-addr.arpa" {
  type forward;
  forwarders { 192.168.248.53; };
};

zone "0.b.3.f.4.6.b.6.0.0.d.f.ip6.arpa" {
  type forward;
  forwarders { 192.168.248.53; };
};