Summary: Today I want to let you know about another free resource that we offer to the general public along with our customers: a free tool that allows you to determine whether your reverse DNS (rDNS) is set up properly.
First, I want to apologize for not being around or posting here last week. I was on a week-long business trip, and while yes, I had a computer with me, I simply didn’t have the time to write. At least you know that it’s really me writing this, and not a ghost-writer, as is the case with some other CEO blogs!
Today I want to let you know about another free resource that we offer to the general public along with our customers: a free tool that allows you to determine whether your reverse DNS (rDNS) is set up properly.
As I’ve explained in more detail here, having your rDNS set up properly is really important. And having it not set up properly (or at all) can have a severe impact on whether the email you send gets delivered or not.
Briefly, rDNS is what allows a receiving email system to take your IP address, and see if it really maps to the domain that your email is supposedly coming from. It’s like Caller I.D. for email: where Caller I.D determines your name from your telephone number, rDNS determines your domain name from your IP address.
And if the domain associated with the IP address from which you are sending email doesn’t match what your email claims your domain should be (such as the “isipp.com” in the email that I send), then odds are very good that your email will get rejected, or, if it is accepted, put into the junk folder.
This tool is very simple - you just type or paste the IP address in question into the form, and hit “submit”:
…and then it will show you where the rDNS for your IP address resolves:
If you don’t have rDNS set up at all, it will give you this message:
And if rDNS is not set up correctly - say it is set up to point to your ISP’s space instead of your domain, you’ll see something like this:
You can check your own IP addresses here at our free rDNS check tool.