IP Whitelabeling is a process of tying a sending domain to a sending IP address. There are three email technology standards that make help ISPs relate sending domains and sending IP addresses: SPF, DKIM and PTR
A sending domain is a part of the "Reply to" email address
For instance, if you are sending from
email@example.com, then the sending domain is
In a typical scenario, our customer would use their sending domain, but the messages will be delivered from our IP addresses, and our domains associated with those IP addresses. Our typical domain would look like:
smtp0021.epmailer.net. When an ISP received such a message, they quickly figure out that your sending domain and our domain associated with the sending IP are not the same.
When this happens, different ISPs will display a warning. For instance, Gmail will display a so-called "via" message.
The point of this message is this: the sending domain is
venturepulse.org, but the email came from IP address associated with domain
If you want to learn more about Gmail VIA, read Extra info next to sender’s name.
You can read our article DKIM in plain English to learn more about DKIM.
The SPF article SPF in plain English will help you learn about SPF
The PTR is also known as Reverse DNS Lookup. It is a mechanism that allows ISPs to lookup a domain associated with an IP address (as opposed to looking up the IP address for a domain, hence the "reverse" lookup).
Normally other ESPs are offering DKIM and SPF configuration. We provide the PTR configuration on demand. Let us know on our Support line if you'd like to get a PTR configured for your domain.
Our service includes configuration of DKIM, SPF and also PTR for better deliverability.
In order to whitelabel our IPs for your sending domain, please add the following configuration to the DNS records if your sending domain:
Add the following to your existing SPF record:
The SPF record needs to look like:
v=spf1 include:spf.epmailer.net ~all
If you have an existing SPF record, do not add a second one! SPF standard allows only one record. Adding a second one will break the first one.