Customers often ask “what are the best configurations to use with PowerMTA”?  ǞǞǞ answer is different for every region of the world. Configuration settings in the US will be vastly different than those in Europe for example, so global settings are not as effective. In this blog post, we take a look at five essential PowerMTA™ configuration tips that will help make your sending infrastructure more efficient and reduce I/O clutter.

利用源指令来确保你的电子邮件标题是正确的

ESPs and many high volume senders send email on behalf of other organizations and often feel they do not have full control over the email headers.   This is not the case, and if best practices are not followed, email almost inherently will end up being routed 到 junk folder. With PowerMTA™, you can add missing data or Message-ID headers.  You can also hide internal sources in the “received header,” or completely disable adding the received header altogether. ǞǞǞ latter is often used to make it look as if the email originated from the sender’s public IP.

通过更明智地使用参数继承来保持清洁的配置

For manageability configurations, it is important to keep them DRY. DRY stands for Don’t Repeat Yourself, and, is an acronym used by software developers.  For example, PowerMTA™ merges the settings from all matching sources. Thus you can often move common settings 到 source 0/0 that matches every IP that connects to PowerMTA™. Except for “always-allow-relaying” of course, which should only be allowed from specific sources. You can also remove settings with obvious default values and further reduce redundant configurations.

With domain directives, all matching domain entries are merged, giving preference to more specific entries, regardless of the order in the configuration. By using sensible default settings for the wildcard domain, you can reduce the configuration to only a few exceptions.  For example, the following setting eliminates the need to enable the use of TLS on “many” specific domains:

<domain *>     use-starttls yes # Use TLS when delivering email </domain>

不要在无效的电子邮件域名上浪费资源

如果一个电子邮件地址的本地部分不存在，你通常会从ISP那里得到一个错误信息。然而，如果域名无效，你可能会遇到重复性的错误，如DNS查询失败，服务器无响应，或服务器拒绝从某一特定域名转发。

PowerMTA™ should be configured not to waste resources on these domains, and focus delivery of resources to valid domains. You can instruct PowerMTA to bounce email if an MX record could not be found for a domain since invalid domains caused by typos often have an “A “record without a proper “MX” mail server record in DNS. You can also use a domain macro combined with black-holing to drop mail known for discontinued domains or domains with anonymous discardable accounts.  In any event, the goal is to keep the configuration “lean” for invalid or less important domains.

根据你自己的数据和经验来应用设置

We’ve talked about this before, but I’d like to reiterate here.  PowerMTA™ has a long list of configuration directives that you can use straight out of the box. Directly copying settings from other sources or matching configurations from another sender environment is not useful, since you might end up with redundant configurations, or even applying settings that are not applicable in your sending environment. The best approach is to keep it as simple as possible and add settings that you understand, and are appropriate in your “own” environment.

Senders in the US require a different configuration than senders in Europe. Furthermore, the settings often depend on the volume of mail, the type of email, and the reputation of the sending IPs.  You can use data from PowerMTA’s accounting files to determine what are the most important domains in your case. By looking 在 bounce reports, you can determine which errors should trigger the back-off mode for example.

记录瞬时错误以监测ISP的节流情况

PowerMTA™会计日志通常用于记录交付或反弹。但是通过启用对瞬时错误的记录，你可以得到大量关于交付的信息，以及如何优化它。大型网络邮件提供商，但也有较小的ISP，对他们接受来自某个IP的邮件数量有限制。当达到限制时，他们会返回一个临时错误，这可以由PowerMTA™记录下来。这些信息可以用来调整IP调剂（预热）或最大发送率的音量，或调整退订模式的配置。

For more comprehensive information on configuration settings, join the PowerMTA forum and don’t hesitate to ask detailed questions about your settings and more specifically about your sending environment.

~ 马腾-奥林, Partner and CTO at 驿站管理