by: Sam C. Chan -- Bravo Technology Center  1/20/03


Which SMTP to use and Why?

There has been much confusion and debates about which SMTP server should you use and why, due to myth and misunderstanding, even among professionals and practitioners alike. Here's the K.I.S.S. guide:

Genreally, there are 3 options:

1. Access ISP. Most people use the SMTP server from their access ISP, such as Frontier, Time-Warner or Localnet, etc. 

2. Hosting ISP. If your company web site and email are hosted commercially, you may access the SMTP from the hosting ISP using your own domain name (such as: mail.yourdomain.com). Most (but not all) hosting plans provide this feature. 

3. Your Own. If you have a Windows 2000/NT/Linux/Mac server on-site, you can operate your very own SMTP server. You can also get SMTP server software for Windows 98.

Option 3 provides the best performance, reliability and control; provided you have the equipment and software to run it, and the technical know-how's to maintain it. The rest of you would choose between option 1 and 2.

Option 1, using SMTP from access ISP is most straight forward. Usually, no authentications are required when you're at your own physical location. Email traffic is streamlined, as all your packets must go thru the access ISP anyway. However, most SMTP from access ISP's are bogged down due to unmetered (read exploited and excessive) usage. "Consumer grade" email services are only considered complimentary (and low quality, low priority) services to provision of an access pipe.

Option 2, If you need "commercial grade" email services, use the SMTP from a quality hosting ISP. Your out-going email traffic would incur extra hops, as they must first travel to your hosting ISP via the Internet, then relayed to their final destinations. While traveling with notebook PC's, this might be the only viable option, as some access ISP's grand access to their SMTP only from within the customer premises.

To summarize (at the risk of over-simplification), in layman's terms: Using your own in-house SMTP server is the best but most complex (hence only done at larger companies). Using SMTP from access ISP is simplest but your out-going email might be delayed by minutes and in some cases many hours. Using SMTP from high quality commercial hosting ISP affords you out-going email that are delivered in seconds (or less). It also works best when traveling. Of course, once delivered, there might still be additional delay at the POP server's end, before the messages are available at the mailbox.

Additional technical info for consultants/resellers: Beware that most high-end hosting plans (especially dedicated hosting, as opposed to virtual/shared hosting) count email traffic toward monthly transfer alotment, while more consumer-oriented plans treat email traffic as "unlimited" and count only HTTP and FTP traffic.