ServerBuddies Support Blog

Enabling DNS clustering on each server

A DNS cluster is a number of nameservers that share records. To optimally configure your DNS cluster, you will need 2 spare servers, both preferably running cPanel DNS ONLY. You will also need at least 1 web server with cPanel/WHM installed.

You can download the cPanel DNS ONLY software here.

http://layer1.cpanel.net/cpanel-dnsonly-install.sea

All machines in the cluster must be running cPanel or cPanel DNS ONLY version 11 or higher. Some features may not work with older versions of cPanel.

Enabling DNS clustering on each server

First, you will need to enable DNS clustering via each server’s WHM interface.

Next, you will need to specify which server(s) you wish to cluster, or share DNS information with.
You do not need to link dedicated DNS servers to each other, or link dedicated web servers to each other.
You will need to sync each web server to its DNS servers.
You should not set a DNS server to sync data back to a web server, as this will put extraneous data on the web server.

Configuring Reverse DNS in WHM

Reverse DNS uses pointer records (PTR) to convert IP addresses into domain names. This is the opposite of forward DNS, which uses A records to convert domain names into IP addresses.

First, add a new DNS zone file. You can accomplish this using the Add a DNS Zone feature in the DNS Functions section of your WHM interface (Main >> DNS Functions >> Add a DNS Zone).

To continue, enter the IP address and proper reverse DNS zone name in the appropriate fields.

To properly format the Domain field in the interface.

Take the first 3 octets of the IP address, Reverse them, and Affix in-addr.arpa to the end. So, for example, the reverse DNS entry for 192.168.0.1 is 0.168.192.in-addr.arpa. After you have filled out these 2 fields, click the Add Zone button.

One you have created your zone file, you can edit it. You can do this using the WHM Edit DNS Zone screen (Main >> DNS Functions >> Edit DNS Zone). Your zone file should already contain an NS entry for every authoritative nameserver associated with your server. To finish this process, we need to add a PTR record for each IP address we wish to name in the last octet of 192.168.0.

After the reverse DNS zone has propagated, run a test to ensure that you have properly configured reverse DNS. To do so, you can use the following command:

If you have properly configured your reverse DNS zone file, the output should resemble the following:

How to set up one domain to be your DNS in Plesk

You must first have the domain you wish to make your DNS already set up in Plesk. You will also need at least 2 IP’s to use for your server. For reference, in this article ’serverbuddies.com’ will refer to the domain name you are using. Make sure to replace this with your actual domain name.

1. Log into your Plesk control panel as Administrator and select the domain from the Domains list you wish to make DNS.
2. Select the DNS icon from your services list.
3. Select the link serverbuddies.com from the Host list, with Record Type NS and Value ns.serverbuddies.com
4. In the Enter nameserver field change the ns.serverbuddies.com to ns1.serverbuddies.com and select OK.
5. From the Tools area select Add Record. For Record type select NS and enter ns2.serverbuddies.com in the Enter nameserver field and select OK.
6. Select from your host list ns.serverbuddies.com with Record type A and change the value to ns1 and select OK.
7. From the Tools area select Add Record again. For Record type leave as A, in the Enter domain name add ns2, in the Enter IP address enter your second IP address that you are going to use and select OK.
8. You should now have 2 Record types with the NS value of ns1.serverbuddies.com and ns2.serverbuddies.com and under the Host list you will also have ns1.serverbuddies.com and ns2.serverbuddies.com with the Record type of A and they will have 2 separate IP’s.

In order to have these added as DNS values for when you add new domains you will need to change the default DNS record in Plesk.

1. Select Server from the list on your left.
2. Select the DNS icon from the Services list.
3. From the Host list select with record type NS and enter ns1.serverbuddies.com in the Enter nameserver field and select OK.
4. From the Tools area select Add New Record. Change the Record type to NS and in the Enter nameserver field input ns2.serverbuddies.com and select OK.

If you want to use 2 separate domains for your DNS this is even easier, because Plesk has already created this for you. You must have 2 domains entered in Plesk and assigned separate IP’s. You would then only need to create a DNS zone template the same way described earlier, only inputting ns1.serverbuddies.com and ns2.serverbuddies.com for your default values.

Reference: http://parallels.com/

Automatically create proxy subdomain DNS entries in WHM.

This can be enabled on the Tweak Settings page.

Enabling this option will allow WHM to automatically create DNS entries for the following 4 subdomains for every user’s account (where example.com stands for the user’s domain):

* cpanel.example.com
* webmail.example.com
* webdisk.example.com
* whm.example.com

These subdomains allow users to easily access the features included with a cPanel installation.

We can use /scripts/proxydomains to create DNS entries manually.

Reference: http://cpanel.net

How to setup Cpanel Dns Cluster’s failure threshold.

This section allows you to specify the number dnsadmin commands that are allowed to fail before a member of your cluster is disabled.

Unresponsive cluster members are disabled in an effort to improve performance.

Global cluster configuration options

If you wish for all of the members of your cluster to remain online at all times, enter 0.

Cpanel recommend setting this value to 10.

Reference : http://cpanel.net/