Will ISP's ever start offering authenticated SMTP service?  Currently, you can use the SMTP server of an ISP if you have an IP address that is owned by that ISP.  What's going to happen if WiFi networks become popular?  As you move from one WiFi network to another, how can you use an SMTP server?  There are three possibilities: (1) You use the same SMTP server and authenticate yourself to the server each time.  (2) There is a standard way to discover the SMTP server on a WiFi network, and you use the SMTP server provided by the WiFi network to send mail. (3) Your computer uses the DNS to find the SMTP server of the mail's recipient and sends it directly.  Perhaps there is a fourth possibility: (4) The WiFi network provider intercepts any TCP connection to a destination port 25 (SMTP port) and redirects it to it's own mail server.

I don't see ISPs rushing to offer innovative features to their customers, so I don't expect authenticated SMTP in the near future.  And that gets me thinking.  Will the business of ISPs eventually become like that of the local phone companies, where there is regulated and unregulated service?  The government would require certain minimal service requirements -- the regulated service -- and would allow other add-on features -- the unregulated service.  Basic SMTP service would be the regulated service.  Authenticated SMTP service at a cost of $3 per month would be the unregulated service.

9:57:29 AM   

The way Internet mail currently works, subscribers to an ISP get their mail via POP3.  The mail transfer is initiated by the subscriber's computer, which acts as the POP3 client.  There is no way for the ISP's mail server to notify the subscriber that he has mail.  Instead, the subscriber's computer must poll the mail server.  Some subscribers set their computer to poll the mail server every 10 minutes, but there is no restriction, and a subscriber could poll the mail server as frequently as he wants.  If every subscriber sets their computer to poll the mail server every 10 minutes that could start to put a real strain on the mail server.  This could become a bigger problem with always-on Internet service.  The POP3 protocol is good for a subscriber on a dial-up account who needs to connect to the Internet, get his mail, and get off.  It's very inefficient for always-on Internet connections.

So, how about this idea: a protocol where either side can initiate the transfer of mail.  This already exists in SMTP as an extension (ETRN).  Many (or most?) cable modem companies prohibit subscribers from running a mail server.  Will this change in the future?

Note: It gets even worse with IMAP4.  Some IMAP4 clients open a connection and keep it open for hours at a time.  Polling is one thing.  Opening a connection and keeping it open for a long time is much worse.  Subscribers should be running IMAP4 servers on their home network, and their mail should be delivered by SMTP from the ISP's mail server.

9:42:03 AM