Name server groups[Link]

To register a domain name and make it available for the outside world, you need to enter name servers. This can be done in the ‘new domain’’ transaction. Registrars who have registered a lot of domains specifying individual name servers will have a hard time when one of these name servers must be replaced. In that case, they will have to update each domain name that uses that name server. Working with name server groups will make this operation much easier.

The name server group mapping is a DNS Belgium specific extension. It allows a registrar to group several name servers in one object, to facilitate the mapping between a domain and a list of name servers.

A name server group is a list of name servers that can be managed separately in the system. A name server group can be linked with a domain name, which has the same effect as linking each individual name server from the group to that domain name. When the zone file is generated, the name server group is replaced by the name servers it contains. The advantage of using a name server group is that you only have to do 1 single update of the name server group in case you need to change, add or delete a name server. This update however will then impact all domains using that name server group.

A name server group can be linked to a domain, the same way a single name server can. It is also possible to mix a name server group with one or more single name servers.

Hint

IP addresses cannot be specified. Therefore, name server groups cannot contain name servers in the same domain as the domain name they will be used for.

Name servers that are in the same domain as the one they are linked to, need an IP address (glue record). E.g. if you register a domain name xyz.be and you want to use the name server ns.xyz.be, you need to add the IP address, otherwise the resolver will not be able to find that name server.

Name server groups however, are created independently from the domain name they will be used for. It is therefore not excluded that one of these domains will be linked to a name server in the same domain. As you cannot add glue records to name servers in a name server group, this will not work and that specific name server will be discarded when the zone file is generated.

E.g. registrar ‘mycompany’ creates a group ‘my-nameservers’, containing the name servers he is using: ns1.mycompany.be, ns2.mycompany.be and ns3.mycompany.be. Afterwards he replaces the existing individual name servers linked with the domains he is managing with the group (including his own domain name: mycompany.be). After the next generation of the zone file, his own domain name will no longer work as the needed glue records are not provided.

Conclusion

If you need to add a name server to a domain that is in the same domain, use individual name servers where you can add the IP address. Use name server groups in all other cases.

Deleting name server groups

A name server group cannot be deleted if it is still linked to one or more domains.