On Sweating the Small Stuff

Over on the Return Path blog, Scott Roth reminds us why it's so important to remember the fundamentals. Great case study for Dillard's, one of my favorite department stores.

Return Path: When is it OK to Use a Shared IP Address?

Return Path's Tom Sather explains when it's OK to use a shared IP address. Basically, when your volume is very low. He suggests that the cutoff be 50,000 messages a month -- below that level, you should be on a shared IP address. Above that, a dedicated IP address is recommended. I personally think there's some flexibility there, but overall, you do have to draw a line somewhere, and it's pretty good guidance. (I usually recommend that senders mailing to more than 100,000 recipients per month utilize a dedicated IP address.)

The one obvious question that I think goes along with this is, when is it NOT okay to use a shared IP address or shared IP address pool? Here are three scenarios where I think it is truly NOT okay to use a shared IP address or shared IP address pool.

ESPs and Purchased Lists

Over on her Word to the Wise blog, Laura Atkins shares a wonderful list of links to almost every email service provider's policy prohibiting use of bought lists or purchased email addresses.

It's funny, working in this business.

Sending mail over IPv6? Authenticate!

Josh over at Word to the Wise explains that as Microsoft brings live IPv6 support for its Office365/Exchange Online Protection email platforms, they're mandating that all mail sent over IPv6 must authenticate with either Sender Policy Framework (SPF) or DomainKeys Identified Mail (DKIM). Unauthenticated mail will be rejected. Read more about it here.

Domains clear.net and clearwire.net have been retired

If you're trying to send mail to subscribers at clear.net or clearwire.net today, you'll notice that all delivery attempts are being rejected, because wireless data provider Clearwire has retired all email services as of April 15, 2015.

Once upon a time, Sprint was the biggest investor in Clearwire, and Sprint's 4G data service was provided over the Clear WiMAX network. Sprint fully acquired Clearwire in 2013, and announced that it would be shutting down the Clear network sometime in 2015. It stands to reason that this email domain retirement is likely related to that overall acquisition and service shutdown.

I was not able to find any information related to the transition of clear.net or clearwire.net subscribers to other domains.