Email 20/20: Why Domain Reputation is Key with the Adoption of IPv6

Do you ever find yourself running out of vital must haves? Maybe it’s shampoo when you really need to look good for a meeting, ketchup when you are having a BBQ with your friends , or pen ink when you are taking notes during a call? When these things happen, sometimes you have to get creative on what you can use in its place.

Well, the internet has the same challenge. Ever since the internet was first created, the Internet Protocol (IP) address has been used as a way to track where communication is coming from. Think of it as snail mail—in order to send something, you need to have a sending address and a receiving address to tell the mail where to go and who it came from. The same goes for the IP address. Each device participating in a computer network uses a unique IP address to be identified and recognized by other systems connected via the Internet Protocol.

So What Did We Start With?
We started with IPv4—which uses 32 binary bits to create a string of unique addresses on the network. It is four numbers 0 to 255 separated by three dots. With this combination, there were about 4.3 billion IP addresses available. Since the internet was not as widely adopted at the creation of these IP addresses, we thought that would be enough.

So What Happened?
The internet took off! And in 2011, we ran out of IPv4 addresses. Enter IPv6—which uses 128 binary bits and contains eight sets of four hexadecimal digits and uses colons to separate each block. There are 3.4 x 1038 (or 340 undecillion—yes, apparently that is a real number) possible IPv6 addresses. Looks like we should be good for a while.

In Practice
Here is an example of what an IPv6 address looks like: 2001:0db8:85a3:0000:0000:8a2e:0370:7334

To add additional complexity—leading zeros in a group may be omitted: 2001:db8:85a3:0:0:8a2e:370:7334

And even more—one consecutive group of zero value may be replaced with a single empty group using two consecutive colons (::): 2001:db8:85a3::8a2e:370:7334

And that’s just the tip of the iceberg….

In our new eBook—Email 20/20: 20 Visionary Ideas to Futureproof Your Email Programwe make some predictions about the future of email. One of those predictions is that with the adoption of IPv6, domain reputation will be a major factor in filtering decisions. The adoption of IPv6 will provide a wealth of IP addresses for all to use that spammers can – and will – exploit.  In order to appropriately assign reputation, mailbox providers are going to rely more on domain reputation to judge incoming mail and marketers will need to maintain a pristine reputation across their domain pool to pass their filters. The best safeguard against potential filtering impact is supplementing existing IP address reputation techniques with domain reputation by utilizing sending best practices.

As means to ease the impacts of this industry progression for Marketers, we have launched domain certification as part of our premier Certification program. By being a part of this elite program, you can bypass certain filtering methodologies at some of the largest mailbox providers—which helps you get to the inbox.

For example, a current client of ours was seeing low inbox placement at Microsoft.

After the implementation of domain certification, they achieved consistent high inbox placement rates of 90-100% across campaigns.


While it is still going to take a bit for the full industry adoption of IPv6, it is important to think about the future of your email program and how to prepare it for what’s to come.

Because it’s never any fun to run out of gas when you have importance places to go!

For more insight on how to protect your email program, read a few other blogs about our predictions for the future:

All Unauthenticated Emails Will Be Blocked from the Inbox
Personalizing the Customer Journey
New Value in Email Data

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