一次发送数千封电子邮件，陷阱/最佳方法？
我正在编写一个 C# 工具（和 System.Net.Mail），它将每周发送大约 4000 封电子邮件。
我可以简单地循环浏览包含 4000 个电子邮件地址的列表并一次发送一封电子邮件吗？ 或者这会导致任何潜在的问题吗？
有更好的方法吗？
谢谢
Im writing a tool c# (and System.Net.Mail) which will be sending around 4000 emails fornigtly.
Can i simply loop through a list of 4000 email addresses and send emails one at a time?
or will this cause any potential problems?
Is there a better way to do this?
Thanks
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首先，您必须拥有rDNS记录，该记录将映射回IP地址到域名。如果没有它，GMail 等邮件服务会将您的电子邮件保留数小时甚至数天。此外，您可能会在收到几十封信后就被列入黑名单。 rDNS 通常可以使用主机的控制面板或通过支持请求进行设置。
其次，不要试图使用 ISP 或 GMail 的 SMTP 服务器。您很快就会用完每日配额。通常不允许发送超过几十封信（据我所知，GMail 为 50 封）。因此，要么从您自己的服务器发送邮件，要么使用第三方服务，例如 auth smtp。
如果您由于某种原因无法设置 rDNS，此类服务也很有用。
PS 如果您的信件内容正常（即它们实际上不是垃圾邮件）并且 rDNS/SMTP 设置正确，您可以以任何速率发送，无需暂停。
First of all you must have rDNS record that will map IP address back to domain name. Without it mail services like GMail will hold your e-mails for hours or even days. Furthermore you may become blacklisted after few dozens of letters. rDNS usually can be set using hoster's control panel or by support request.
Second, don't be tempted to use your ISP's or GMail's SMTP servers. You will quickly run out of daily quota. It is usually not allowed to send more than few dozens letters (50 for GMail AFAIK). So either send mail from your own server, or use a 3rd party service like auth smtp.
Such services are useful also if you're unable to set rDNS for some reason.
P.S. If the content of your letters is OK (i.e. they are not spam actually) and rDNS/SMTP are set correctly, you can send at any rate, without pauses.
只要您不违反任何服务器限制（例如内存或磁盘空间），从技术上讲就没有问题。然而，您会遇到 ISP 和邮件转发器的问题，他们可能会阻止您的域接收垃圾邮件 - 无论正确还是错误。
Provided you don;t break any server limitations, such as memory or disk space, technically there is no issue. However you will run into problems with with ISP's and mail forwarders who may block your domains for spam - rightly or wrongly..
您可以一次性发送 4000 封电子邮件，但您确实面临着很快被标记为垃圾邮件发送者的风险。
您最好的选择是“突发发送”，因此可能会立即发送 100 封，然后在 10 分钟内再发送 100 封，依此类推。
如果您这样做，那么您就不太可能被视为垃圾邮件发送者。
You could send the 4000 emails in one go, but you do run the risk of getting marked very quickly as a spammer.
Your best option is to 'burst send' so send maybe 100 straight away, in 10mins send another 100 etc.
If you do it this way your are less likely to be seen as a spammer.
检查发送邮件的机器是否具有有效的 PTR 记录 - 即，如果您使用 IP 1.2.3.4 从 www.example.com 发送邮件，则 1.2.3.4 上的 PTR 查询将返回 www.example.com；我会研究SPF和DKIM 也是如此。
一些电子邮件主机有传入速率限制（例如 Hotmail 过去使用过）-“如果您每分钟向我们发送超过 x 封电子邮件，您将获得更高的垃圾邮件分数”。我有一个脚本来“搅动队列”，以便降低单个服务器的每分钟速率。
另外，检查一下 - 它有关于电子邮件内容的大量好建议，但这有点偏离主题。
Check that the machine sending the mails has a valid PTR record - i.e., if you're sending from www.example.com with IP 1.2.3.4, that a PTR query on 1.2.3.4 will return www.example.com; I'd look into SPF and DKIM, too.
Some e-mail hosts have an incoming rate limit (e.g. Hotmail used that in the past) - "if you are sending us more than x emails/minute, you get a higher spam score". I had a script to "stir the queue", so that the per-minute rate to a single server was lowered.
Also, check this - it has plenty of good advice on e-mail content, but that's slightly off-topic.
除了上面提到的之外，请务必设置足够的日志记录。
也就是说，您应该记录已发送的电子邮件，这样如果您需要重新发送电子邮件，您可以确保不要发送重复的电子邮件。
此外，您还可以设置一个应用程序来记录退回的电子邮件，并使用它来删除地址等。
您当然可以编写自己的软件或购买一些软件。
http://www.quiksoft.com/bouncebuster/
In addition to what has been mentioned above, be sure to set up adequate logging.
I.e. you should log sent emails so if you need re-send emails you can be sure not to send duplicates.
Also, you can set up an app to log bounced emails and use this to remove addresses etc.
You can of course write your own software or purchase some.
http://www.quiksoft.com/bouncebuster/