BLOG

Delivery can be counter-intuitive

We all know that receiving ISPs rate limit incoming email. With the volumes of mail that they’re currently dealing with they must do that in order to keep their servers from falling over.

A client was dealing with rate limits recently. These were not typical rate limits, in that the recipient ISP was 4xxing mail. Instead, the recipient ISP was not accepting any incoming connections. The client was having a bit of a difficult time understanding what was happening and why the problem wouldn’t be solved by increasing the rate at which they were trying to send to the ISP.

Imagine if you will, that at every ISP there is a reception desk that manages the incoming calls. The receptionist is under orders from the to limit the number of calls coming in. When the phone rings, the receptionist can do any of the following:

1) answer the phone and put the call through (250 message accepted)
2) answer the phone and put the caller on hold (connection hangs or delivery is slow)
3) answer the phone and tell the caller to call back later (4xx message deferred)
4) fail to answer the phone (no connection at all)

The delay the client was seeing was #4, in that they were attempting so many connections at once that the ISP was just not answering.

In this case, reducing the number of connections attempted worked. The “receptionist” was not so overwhelmed by the number of ringing lines that she was able to actually answer all the calls and put them right through.

While lowering the rate at which the client was attempting to delivery seems counter intuitive to getting improved delivery, because we understood the mechanism we could lower rate and get an increase in delivery.

Comment:

Your email address will not be published. Required fields are marked *

  • OTA joins the ISOC

    The Online Trust Alliance (OTA) announced today they were joining forces with the Internet Society (ISOC). Starting in May, they will operate as an initiative under the ISOC umbrella. “The Internet Society and OTA share the belief that trust is the key issue in defining the future value of the Internet,” said Internet Society President and CEO, Kathryn Brown. “Now is the right time for these two organizations to come together to help build user trust in the Internet. At a time when cyber-attacks and identity theft are on the rise, this partnership will help improve security and data privacy for users,” added Brown.No Comments


  • Friday blogging... or lack of it

    It seems the last few Friday's I've been lax on posting. Some of that is just by Friday I'm frantically trying to complete all my client deliverables before the weekend. The rest of it is by Friday I'm just tired. Today had the added complication of watching the Trumpcare debate and following how (and how soon) it would affect my company if it passed. That's been a bit distracting, along with the other stuff I posted about yesterday. I wish everyone a great weekend.1 Comment


  • Indictments in Yahoo data breach

    Today the US government unsealed an indictment against 2 Russian agents and 2 hackers for breaking into Yahoo's servers and stealing personal information. The information gathered during the hack was used to target government officials, security employees and private individuals. Email is so central to our online identity. Compromise an email account and you can get access to social media, and other accounts. Email is the key to the kingdom.No Comments


Archives