www.hahosting.info

Extra Services: Reverse DNS

DNS is the backbone of the internet – it’s what binds names (such as www.sheffielddatacentre.com) to IP addresses, allowing servers and computers to talk to each other.

Reverse DNS (or rDNS) is the opposite to how normal DNS works, instead of translating a host name into an IP address, rDNS translates an IP address into a host name. When a domain name has a valid rDNS, it can also be access by just using the IP address – for example if you type “188.94.74.11” in your web browser you will be redirected to our www.hahosting.com website.

Why would I want Reverse DNS?

Most commonly rDNS is used for mail servers. When an mail server sends out an email for a domain, the receiving server commonly does a “reverse lookup” on the MX record to determine if the IP address sending the email is actually the server it’s supposed to be. Email systems such as AOL, 1&1 and even our own Hosted Exchange service now use this as a basic check before accepting email.

For example:

The domain bloggs.com has a MX record of mail.bloggs.com, with an IP address of 1.2.3.4

That server sends an email to someone at fred.com, fred’s email server will use Reverse DNS to check the MX record of bloggs.com (mail.bloggs.com) is actually 1.2.3.4.

If it’s not it may block the message from being accepted, or mark it as suspicious.

Additionally some security software and enterprise management systems use rDNS to ensure the IP address of the server connecting is actually the server as specified in it’s hosts file.

The Sheffield Data Centre and rDNS

We offer Reverse DNS to all customers of the Sheffield Data Centre free of charge. Any customer who has physical or virtual servers hosted with us can have their IP address registered against a hostname.

Simply raise a support ticket with us once your server or colocation is live, and we’ll sort the rest.

Redundancy & Security

We operate a redundant pair of Name Servers, each connected to a different physical switch, and each physical switch connected to a different interface on the firewalls.

Servers are only allowed to accept DNS updates from our management network, so only genuine updates can be propagated to the internet as a whole. As members of RIPE, our DNS servers are registered and only our servers are authoritive for our IP address ranges.

Contact us

To setup your Reverse DNS host for your servers in the Sheffield Data Centre, call us on 0114 228 0022, or email support @ hahosting.com to open a support ticket.

All prices exclude VAT.