Custom DNS – The Last Link for Your Reputation & Branding

There is a dizzying array of information, discussions and banter regarding the importance of sender reputation, however very little substance about how the process technically works. Even more surprising is the continuous debate among ESPs as to whether its better to have a client on a shared IP address verses a unique IP address. Please tell me how a sender establishes a good reputation using a shared IP address? I still haven't figured out the risk logic to this yet. What's most shocking is that very few ESPs offer their clients custom DNS. What is custom DNS you ask? It's when you have the ability to send email from your own domain name such as This email address is being protected from spambots. You need JavaScript enabled to view it. instead of your ESPs mail server domain such as This email address is being protected from spambots. You need JavaScript enabled to view it.. This involves pointing certain DNS records to the unique IP address your ESP provides. The IP has to be unique since reverse DNS needs to be configured as well and only one reverse DNS is permitted per IP address. Instead, many ESPs allow their clients to "spoof" a sender email address, violating many ISPs acceptable use policies (however rarely enforced).

The importance of custom DNS stems from the fact that it's the last link in ensuring your email sending reputation and one that is rarely implemented. In fact, if you don't have a custom DNS and a unique IP address, you will not be able to participate in sender verification, white listing and reputation management programs. Also, many corporate phishing filters block links in messages that point to other domains other than the receiving authenticated domain. Meaning if you send an email from mx345.myesp.com and have a link in your message that is pointing to yourwebsite.com you have a higher probability of it being filtered in a corporate network environment.

So what's a concerned marketer to do? The first step is to get a unique IP address. If you send a significant volume of email and your ESP doesn't offer a unique IP address then its time to consider a new ESP. The second step is to ask your ESP to help you with your custom DNS. They should provide you with a string of DNS entries that include authentication. If your lists are relatively clean and branding is important, choose a derivative of your corporate domain name such as email.yourdomain.com or click.yourdomain.com. If your list gathering practices are even slightly questionable then you should purchase a domain specifically for email marketing. If your ESP tries to charge you an arm and a leg for this service kick them in the shins and demand that they do it for free. It should take an experienced network admin no more than 15 minutes to get your account configured correctly.

Custom DNS is the only way to go with email marketing. The setup process will take a little extra effort however it will pay dividends with email reputation management, branding and overall trust with your recipients.