Reverse DNS entries for MX records - UK Web Hosting | Dedicated Server Windows and Linux VPS Forum

**KellyJ** · #1 (**permalink**) 02-05-2007, 10:52

Hi,

DNSReport.com indicates a Fail for Reverse DNS entries for MX records.

Support asked me to let them know the hostname for which I wish to set the RDNS.

Can someone please help me understand what RDNS means, and what 'hostname' means in this context?

James

**Ryan** · #2 (**permalink**) 02-05-2007, 12:18

Hi James,

Reverse DNS is a method of resolving an IP address into a domain name in the same way as the DNS resolves domain names into associated IP addresses. For instance, when a lookup is made on the IP address 1.2.3.4, it should come back with host.mydomain.com.

**KellyJ** · #3 (**permalink**) 02-05-2007, 12:47

Thanks Ryan,

That was a very clear definition, hence the term 'Reverse' in RDNS.

So why is Support asking me for information they already know (my IP address and domain name)?

When they ask me what 'hostname' I wish to set the RDNS, are they referring to something other than the domain name?

It appears I need to give Support some information, so that they can resolve the Fail issue in DNSReport, but I don't know what information they require.

James

**Ryan** · #4 (**permalink**) 02-05-2007, 14:39

Hi James,

Our support team just need the IP address and the domain name where you wish to point the rDNS.

**KellyJ** · #5 (**permalink**) 02-05-2007, 15:06

Ryan,

So, if my IP is 1.2.3.4 and my website hosting is www.mysite.com, is the information required then 1.2.3.4 and mysite.com?

Since Support already have that information, I'm wondering if there are other possibilities I'm unaware of.

In your first example, you used host.mydomain.com, rather than the domain name mydomain.com. I'm not familiar with that format. Is there some significance in the word 'host'?

James

**eUKhost.com** · #6 (**permalink**) 02-05-2007, 15:14

Hello James,

it makes no difference if you wish to add a rDNS for a hostname, subdomain or main domain. all we need to know is the domain name for which you need rDNS.

**KellyJ** · #7 (**permalink**) 02-05-2007, 16:17

eukhost.com,

Clearly, there are gaps in my knowledge, when I don't even understand the question being asked of me, though you and Ryan and Support understand.

I believe I know what a domain name is (e.g. mysite.com), but I don't know what a 'hostname' is.

The website hosting domain management was transferred to eUKHost a few days ago. The website hosting is running, but I'm having problems with email, possibly due (in part) to the subject of this thread. (The relevant ticket number is #BJU-65831-847)

To resolve remaining email issues, I *need* help from eUKHost, as I don't have the knowledge myself, and I'm trusting eUKHost will offer that help.

When you say "all we need to know is the domain name for which you need rDNS", I don't understand what you mean. I probably need to go back to basics. I know the domain name as registered with Nominet, e.g. mysite.com.

So, if I answer Support by stating (a) mysite.com and (b) the Primary IP Address in my welcome letter, will that do?

James

**flesso** · #8 (**permalink**) 02-05-2007, 16:37

A hostname is the name of an address.

For example:

flesso.com - This is a hostname.
bob.flesso.com - This is a hostname.

So, basically, a hostname is an A record to cut it short, in the 'bob.flesso.com' example, 'bob' is the hostname.

So, the hostname in your case would be 'mail.kellyj.com'.

Just add the A record for 'mail.kellyj.com', and tell support that you want the hostname to be 'mail.kellyj.com'.

If thats all a bit confusing, I'm stupid, if not, I'm happy to help.

**KellyJ** · #9 (**permalink**) 02-05-2007, 16:53

flesso,

I hope none of us is stupid, we just have different levels of knowledge!

You have been helpful, at least by giving an example I can work with.

Using your example hostname, but substituting my example domain name, you are suggesting I tell Support that the hostname is mail.mysite.com?

And, for the IP address, do I tell Support its 1.2.3.4, but substituting the Primary IP Address from my welcome letter?

James

**flesso** · #10 (**permalink**) 02-05-2007, 16:57

Yes, you tell support your IP address.

Like:

1.2.3.4 - mail.mysite.com

Yes we do all have different levels of knowledge...

**KellyJ** · #11 (**permalink**) 02-05-2007, 18:09

flesso,

Thanks for your help, I can now proceed to let Support know the hostname.

I realise now that Ryan's reference to supplying an IP address to Support was probably just for identification, and I read something into it which wasn't intended. Indeed, everytime we create a new support ticket, we include the relevant IP address.

James

P.S. I won't reveal what you edited out...!