General Guidelines


Our goal is to make sure that our customers receive the mail that they want and that we keep unwanted mail away from our system or at least out of the customer Inbox. As a member of MAAWG, Time Warner Cable recommends that organization's Sender Best Communication Practices (PDF document) as a good place for you as a sender to start in helping us meeting our goal.

Beyond the MAAWG BCP, the rules of the road here aren't much different than what mailbox providers have been telling senders for some time now:

  • IPs connecting to our inbound mail servers must have resolvable reverse DNS (i.e., PTR) records; if the connecting IP doesn't have a resolvable PTR record, the connection will be refused.
  • IPs connecting to our inbound mail servers should not be dynamic IP addresses; we use several third party lists of dynamic address space to reject connections from IPs believed to be dynamic.
  • Send mail that our customers want to receive; this is best accomplished through a confirmed (or double) opt-in process of building your mailing list, sending mail that's relevant to your subscribers, providing an unsubscribe mechanism and honoring it, and enrolling in our feedback loop
  • Handle your bounces, especially those tell you that the address does not exist here. We reject SMTP RCPT TO commands during the SMTP transaction when the intended recipient does not exist here, and we do it with explicit text - 550 5.1.1 - Invalid mailbox: RECIPIENT@SOMETHING.RR.COM RECIPIENT@SOMETHING.RR.COM . While there has historically been a belief among some senders that some ISPs aren't being truthful with such error messages, know that with Time Warner Cable, "550 5.1.1 - Invalid mailbox" means that the email address does not exist here or is not an active account here.
  • Separate your mail streams, if appropriate - If you send both promotional (i.e., marketing) email and transactional email, chances are that you see different complaint and delivery rates for one vice the other. It is usually thought a good practice to separate such mail streams, so as to ensure that you don't pollute the clean mail stream.
  • Maintain a consistent identity when sending - If you always use the same identity (email address and domain) when sending wanted mail to our customers, your mail will be that much more likely to be easily recognized by our customers as mail that they want. You've got a brand that you want to market, and your sender address, your subject lines, and even your content should all make your mail easily identified as being associated with your brand.

Sending email is easy; properly marketing your business's products and services through email is hard, and if you don't do it correctly, your mail can end up looking like spam and being treated accordingly. There's much more to it than just maintaining an addressbook that you send to every few days. Think about what your business's core competencies are; they're the products and/or services that your business sells, and email marketing is not usually among those core competencies for many senders. If that sounds like you, there are many companies out there who can help you better market your business through email, and allow you to focus your efforts where they belong, on serving your customers.