Apparently we've been restricted (though packet filtering) to some arbitrarily small and untenable number of emails a day by some bankrupt ISP (and they say that's how it's always been chortle). We've been using our own mail server for the last 15 years, and only recently they've been giving us guff.

Is there a way for a legitimate business to email their clients, who really want to receive these emails, by bypassing the ISP? The way we've been doing it is by breaking up into 20 or 30 emails, but that gets complicated and requires a lot of manual labor by the receptionist, and unless she's really careful we wind up emailing lots of people twice.

So what are my options (Hosted Email, Lithuanian Proxy Server, Different ISP, not writing awful PHP that sends out zillions of emails and gets us blacklisted)?

  • Can you clarify if the ISP is blocking how many email address to can include in a single email (such as 20 or 30 in the CC or BCC line), or is the ISP limiting your account to only send out a total of 20 or 30 emails a day. Jul 7, 2009 at 14:19
  • I'm not completely certain because we haven't really been able to experiment and they're very vague about their terms of service. But the last time we wanted to mass email our clients we had to do 20 to 30 recipients in a single email, although we could do them all in one day. But I believe there is a daily and monthly cap although I don't know what it is. Jul 7, 2009 at 14:22
  • If they do not limit the number of email messages being sent then you might want to look at using MS Word to do an e-mail mail merge. It will create and send an email for each email address in a list. Therefore each e-mail would look like it is from you to a single person, and look as if you wrote each one. Not very spammy looking. The other huge benefit in your situation is that it is fast and would not take your receptionist all day to do. I still recommend MailChimp though. Jul 7, 2009 at 14:27

10 Answers 10


get vps / cheap dedicated server and set up smtp relay there. use alternative port for smtp [ in worst case even 443 although traffic you'll sent will be smtp ].

remember not to set up open relay - filter based on src ip addres - that would be ip address of your server at current isp. i'm doing this kind of set-up for mass mailing, mostly because ips of shared web hosting i use in one case are blacklisted.


Move to an ISP that supports the type of traffic you want to generate.

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    Upvoted. The best answer isn't always a technical one - if the company you are currently with will not give you the service you require then it may well be time to take your custom elsewhere. Jul 7, 2009 at 14:44
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    +1, the only sensible answer here. There is probably a reason why this ISP is near-bankrupt. Jul 7, 2009 at 14:52
  • This is the best answer not only because of the technical impossibility of attempting to circumvent someone else's firewall rules, but if the ISP is doing the Right Thing by blocking all outgoing SMTP connections to anything but their own SMTP server, a hosted SMTP server isn't going to help you.
    – Ernie
    Jul 7, 2009 at 15:59
  • Heh, this is a big ISP and I work in a small town. Jul 7, 2009 at 16:39
  • @erniedwork: I can't speak to the poster's ability or inability to switch ISP's (I've worked in some nasty backwater rural areas where there is only one choice, aside from dial-up), but many hosted SMTP offerings allow you to submit on alternative ports or via SSL to bypass deep-packet inspection. Jul 7, 2009 at 17:25

Get some hosted email service that does what you want. Seems fairly straightforward to me.


"Hosted email" means a whole spectrum of offerings, from the very simple to the very complex (hosted Exchange, etc).

If you're just looking to be able to send arbitrary SMTP to the Internet w/o running afoul of your ISP's deep-packet-inspection, you might be looking for something like the MailHop Outbound service from DynDNS.com. This service, as an example, lets you specify their SMTP servers as a "smart host" in your existing on-site mail server (letting you use a variety of destination port numbers, assuming your on-site SMTP server supports using non-standard port numbers) such that your existing on-site mail server delivers outbound email to the DynDNS.com servers, which in turn perform final delivery to the Internet.

As Richard West has pointed out in the comments, the Mailhop Outbound service, at its default pricing level, only allows 150 relays / day. You can purchase more relays / day as necessary, or you can look at other providers who might offer more relays / day or relays / dollar. Bandwidth isn't free, so you're going to find transfer limits of some type (bytes or relays per day, typically) with most providers.

There are a variety of providers out there that can provide this level of service. Be aware that none of them take too kindly to unsolicited commercial email, so be sure that you don't run afoul of their policies with what you're sending.

If you're just looking for the ability to do "mass mailings" you might be happier with one of the mass mailing services mentioned by other posters.

  • I'm downvoting this because it's too obvious. It's a good answer though and I'm sure someone else will up vote it to give you a net gain of at least 8 points. Jul 7, 2009 at 13:59
  • Well I upvoted it again. Why would you downvote someone for giving the best answer to the question? We often recommend to people they take out an account with someone that does authenticated SMTP and allows mass mailings. Then you route your mailshots through them and use authentication. Jul 7, 2009 at 14:04
  • If it were so obvious the poster wouldn't be here asking for a way to do it differently. Jul 7, 2009 at 14:09
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    FYI - MailHop Outbound from DynDNS.com only allows 150 relays/day. Jul 7, 2009 at 14:47
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    @Richard: That's a misstatement on your part. It is true that the default pricing only allows 150 relays/day, but you can always buy more. Jul 7, 2009 at 14:59

We use Constant Contact to do email blasting to our customers. It works wonderfully, has very detailed reports, and seems to be pretty inexpensive.

With that said, to avoid the problems you're having with your ISP, I would consider running your own mail server. Without knowing your company's IT infrastructure, I can't really make a good suggestion, but I'm partial to Microsoft Exchange. If you have a small business, look at running Small Business Server.

  • They restrict that traffic, how does running my own mail server help? Jul 7, 2009 at 14:05
  • Sorry, your original question does not indicate that they restrict any traffic. It does, however, indicate that they simply limit the number of emails you can send per day. I assumed you were using your ISP's POP service and they were limiting you there. Regardless, look at Constant Contact -- it should do everything you want and more. Jul 7, 2009 at 14:09
  • Can I use constant contact with a custom programmed app or do I have to generate some sort of email list and have them manage it? Jul 7, 2009 at 14:19
  • Take a look at their Email FAQs here: constantcontact.com/email-marketing/email-faq/index.jsp I don't think they have an API for their service, but you can certainly create your own HTML to use for the email. It looks like they accept contact lists in .txt, .csv, and .xls formats. Jul 7, 2009 at 14:30
  • @peter MailChimp has API support if you need that level of integration Jul 7, 2009 at 14:30

I recommend you look at MailChimp.

ISP's often limit how many recipients an e-mail message can contain in an effort to fight spammers.

Using a service such as MailChimp also provides you with a ton of analytics to see the open rate, bounce rate, etc.

This also provides your users with an easy way to opt of of receiving your e-mail messages.


I have setup my own linux mail server that sends direct to the internet. This seems to work fairly well. All my mail clients (windows) then has the linux mail server's internal ip address as their smtp server.

  • Yeah so do we it's still going though the ISP. (Not using some webmail) I should have explained that I guess. Jul 7, 2009 at 14:03
  • I think you're suggesting that your ISP is doing some kind of deep-packet (or not-so-deep) packet inspection and blocking / manipulating traffic bound for destination TCP port 25. If that is the case, your only real option is some kind of hosted solution since traffic to Internet email servers from your machines will, by definition, need to be bound for destination port 25. Jul 7, 2009 at 14:11

A good, hopefully easy but not necesarily the cheap solution would be to get a good ISP (as others have hinted at too). A business contract with a good ISP does not limit the kind of traffic you generate in any way.

Another solution, also good and will probably be quite cheap also, is to get a VPS (Virtual Private Server) where you most definitely will not have any limitation on the kind of traffic. This also saves you from having to manage a stable server environment (redundant power, cooling and internet access) at your company office.


Updated on July 7th, 2012

If your current SMTP mail server(s) does not support your email list size or sending frequency, there are some options.

  1. You can use a secondary SMTP mail server such as SMTP2Go, AuthSMTP or Socketlabs to relay your larger group email campaigns, or
  2. upgrade to a business account with your provider. For example, Comcast residential customers can send 1,000 emails/day, but Comcast Business customers can send 24,000 emails/day, and GoDaddy customers are allowed to send 250 emails/day by default, but can purchase additional SMTP relays (in packs of 50); or
  3. acquire group email software with an internal SMTP engine that allows you to bypass the outgoing SMTP mail server of your ISP or web host and send directly from your computer to your recipients. Direct Sending is most effectively used by larger companies with established email/IP/domain sending reputations; and direct send messages originating from a shared/dynamic IP will most often be rejected by recipient mail servers as it appears to be sent (and often is) from a home-based user or spammer; or
  4. get your own managed web/mail server.

For more information about options to send more email than allowed by the hourly and daily limits imposed by your ISP or mail server read:

Email Send Limits and Options.

For a comprehensive list of the hourly and daily email sending limits for the major SMTP mail server hosts, read:

Email Sending Limits for ISP, Web Hosting and Free Email Providers

Best regards

Tom O'Leary


Consider a Google Apps account. They're free up to 50 users, and reasonably priced thereafter.


Is it even moral to answer this question with a technical answer? If the person asking this question is not a spammer (and to be honest, that doesn't seem likely), then the information we provide would help any spammer googling for this information.

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    -1 for defamation of character. I'm an accidental spammer (there's a difference) Jul 7, 2009 at 16:20
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    I have to agree with the Peter here. I am not sure it is our job to judge the moral character of fellow SF's. I am instrested in this question because my mail server is with GoDaddy who causes us many problems in regards to email. What is spammy about that? @erniedwork, I would say if you feel that there is only bad to come of the answer, don't answer.
    – Matt
    Jul 7, 2009 at 16:27
  • Accidental spammers are users with computers or networks that have viruses sending spam, not businesses trying to send bulk e-mail. Regardless of your reasons for sending bulk e-mail, you are trying to circumvent your ISP's security and anti-spam measures. Any information we give to successfully defeat those measures can also be used by those with malicious intent as well as those whose intentions are pure and just. The principle of the matter is that we should not help people try to defeat security.
    – Ernie
    Jul 7, 2009 at 17:49
  • As an addendum to my last comment: Perhaps the best possible solution to "too much security" is "ask nicely". Your systems/network administrator would much rather be told the problem so that he can fix it for you, than to be bothered to plug yet another security hole in the firewall after you find a workaround.
    – Ernie
    Jul 7, 2009 at 17:56
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    There's nothing immoral about giving advice to circumvent illegitimate policies. Email sent to you with a good intent is not being sent immorally regardless of whether or not you wanted it or not. ISP's are the ones who are acting immorally when they stifle our most efficient means of mass communication with our clients. And as an addendum, try asking Charter to do anything for you! Jul 7, 2009 at 19:27

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