Help With A 50,000 Mailing List


New Member
I have a registered customer e-mail list that i send a weekly email to. I do have my own dedicated server for my website, but the mail server is not too stable, and it does bog down the server and even has crashed the system a few times. I decided to start using MaxBulk mailer, and use my Mac as the mail server. This has actually worked really well, though i do get a lot of complaints from customers who tell me they don't get our weekly e-mails even though they they are on the list.

i can not send the emails through my own domain, for the reason i mentioned above, and obviously even though i pay over $100 a month to AT&T for my business DSL line, they won't let me send more than 250 emails a day. So i have been using the SMTP host. This has worked fine for months. The last weeks email though, after sending out a few hundred e-mails, i get an "Error - Mailbox Unavailable" message on all the e-mail address after that (yes, all 49,500), so now no one is getting my e-mails. I have not changed anything, so i can not figure out what is wrong. I called AT&T and they said my port 25 was not blocked, so i know it was not that.

i also am unclear on how the mail is going out in the first place. Right now i belive it uses the PostFix application to send the mail... could it have something to do with that?

any help you can give me would be appreciated. If you need any more info, let me know.




Staff member
If you use a recent Mac OS X version you are very likely using PostFix. Older versions were using SendMail. When sending e-mail in fact you have the choice between using your ISP, your web host or your own dedicated SMTP server (in that case PostFix).

If you decide to use your own server (on Macintosh, Windows, Linux and any other OS) you have to make sure that your IP address is not on any listings of dialup or dynamically allocated IP addresses (Residential IP) and make sure the IP address you are using is registered to a domain name preferably with an MX record. Also be aware that some services like AOL will bounce your messages as soon as they detect they have been sent from a residential IP, an IP that belongs to a range of IPs for DSL/Dialup connections, including static IPs, or that IP has no reverse DNS (PTR) or no domain assigned to it. Following our tests, using our own SMTP server may generate between 20 and 30% additional bounces. The question is, can you accept that up to 30% of your customers will never get your messages?

The best solution is without doubts to purchase a web package. Most web hosts provide you with a dedicated SMTP server. Particularly if you are a business and you have a legitimate need to communicate with your customers, your web host should provide a reliable SMTP service. They may also have sending limitations, but they are likely much less restricted than an ISP mailserver. The only condition is your ISP not blocking port 25.

Needless to say that all those limitations are related to spam fighting.