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Home > Documentation in English > AlternC Accounts administration > DNS Slave Servers and

DNS Slave Servers and

Word of warning

You must have a thorough knowledge in the DNS system, or precise instructions from your hosting provider or system administrator when changing the values in both pages.

It changes the way the domain lists and domain name resource records are exchanged between your server and the secondary dns servers.

You should leave this management to these people if you don’t want to bring your entire server and all your domains in a complete havoc!

Again, please remind the following admin control panel sections are not to be messed with unless you know what you are doing.


These features are natively supported by AlternC.

To enable a server as a master server, it is required to install on it the alternc-slave package.

if [[ ! $(dpkg -l alternc-slavedns) =~ "ii" ]] ; then aptitude install alternc-slavedns; fi;

Also, please note that if you want to enable different DNS servers than the ones you provided during the installation of AlternC, you must edit the /etc/alternc/ file and reload the alternc.install script.

# vim /etc/
   ... edit the following lines ....
   # Secondary DNS hostname
    ... save and run ...
# /usr/sbin/alternc.install


AlternC allows you to define some servers as DNS slaves or masters for your domain zones.

A good use case for this feature is when you have many servers (slaves) and you want to use your own name servers (masters). In this case, you’ll want the master server to read the list of domaines installed on each alternc slave, regularly retrieve the zones associated with these domains and add them to the name server database.

Note that the terms "master" and "slave" meaning in this documentation differs from the meaning of master / slave in classical DNS documentation, ie. primary/master and secondary/slave name servers.

Alternatively, you could also want to use this feature to replace entirely your registar DNS. In which case, you might want to read the information regarding the service.

Manage allowed IP Addresses for slave DNS transfers

To enable a server to retrieve the domains zones, you need to allow its individual IPv4 address (/32) or allow subnets (ex:

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Manage accounts for slave DNS transfers

To enable a server to retrieve the domains list, you need to create a http-auth access.

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This will allow the server to access the url http(s)://user:password@yourdomain.tld/dom_list.php which provides a one-domain-per-line document.

The free service

The AlternC association provides a free service for users who need DNS servers to replicate their zones.

The servers are hosted in high quality datacenters to provide a solid resilience in case of failures.

The service is available on

To make it work, you need to allow the server IPs and provide them an http authentification as previously explained on this page.