Sending Email Campaigns

Why does Interspire Email Marketer use my Bounce Address instead of my From Address for sending emails?

To understand why Interspire Email Marketer does that, you must first understand how sending emails over the Internet really works.

When you compose an email in your email client and click “Send”, what the email client does for you is to add some additional information to your message like “Date” and “Return-Path”. These additional fields are called Email Headers. The Return-Path is the email header responsible for specifying the bounce address according to RFC 2822. The From and To addresses, as well as the Subject line are also part of the Email Headers – it’s like a letterhead being added to a letter written on paper.

After that your email client connects to your outgoing SMTP server and sends it:

  • your email address (MAIL FROM)
  • the address of the recipient (RCPT TO)
  • the Email Headers and Email Body

From there on, the SMTP server uses this data to construct an envelope. Just like in paper mail – the letterhead and letter body (Email Headers and Email Body) are sealed inside the envelope, while the sender and recipient addresses (MAIL FROM and RCPT TO) are stamped on the envelope. Very similar to a postal truck delivering a letter to another postal office, the SMTP server relays your email to other SMTP servers until the message reaches its final recipient.

However, imagine the recipient address isn’t valid. A postal worker will most probably examine the sender address as written on the envelope and send the letter back to that address, unless he belongs to that small percentage of really curious postal workers, who will actually unseal your envelope, examine your letter and send it back to the address specified on the letterhead instead.

The reason for that metaphor: When email is transported via SMTP, most MTAs examine only the information that’s on the envelope and only a very, very small percentage of MTAs will actually open that envelope and examine the Email Headers and Email Body. This means that the Return-Path header will very likely be ignored, so if a message bounces back the bounce will almost surely arrive at your From Address.

At the same time, when a recipient opens a message his email client will actually examine the Email Headers and thus display the From Address as specified in them and not on the envelope.

Knowing that fact and being aware of the common problem with Return-Path headers being ignored by MTAs, Interspire Email Marketer (acting as the email client) sends your email campaigns with the bounce address specified as a MAIL FROM/Envelope From to make sure that all bounced emails will arrive at the proper mailbox. It also adds your From Address in the Email Headers to make sure that all recipients will see your actual From Address when they open your campaign.

Does Interspire Email Marketer have sending limits?

Technically, there is no limit to the number or emails which Interspire Email Marketer can send. When dealing with high volumes of email, the capacity to send has more to do with the configuration of PHP, MySQL and most importantly the MTA (mail trasfer agent). Most servers use “out of the box” configurations of an MTA (Sendmail, QMail, Postfix, Exim, etc). We HIGHLY advise that you retain the services of an MTA expert if you intend on using Interspire Email Marketer to send more than 75,000 emails per campaign. That said, IEM does support a configuration option to throttle the number of emails sent per hour. You can refer to the settings page for more details on how to leverage this option.

Does Interspire Email Marketer send one email at a time, or all the emails at once?

Interspire Email Marketer sends one email at a time. Sending multiple emails at one time, or using the CC / BCC fields cause emails to be marked as spam by email clients and should be avoided.

How do I set Interspire Email Marketer to send emails from my own SMTP server (mail server)?

Interspire Email Marketer allows you to specify your own mail server. This will make Interspire Email Marketer send out using a different mail server to the default one set up on your server. For all versions before Interspire Email Marketer , the SMTP server can be found by editing the User account for the current user. For all versions after Interspire Email Marketer, the SMTP server settings are on the settings page. You will need to select the option to ‘Use SMTP Server’ and then fill out the appropriate details:

  • SMTP Hostname: This is your new SMTP host name or IP address (
  • SMTP Username: If your server requires authentication you need to add your user name here.
  • SMTP Password: If your server requires authentication you need to add your password here.
  • SMTP Port: If you are using a non standard port number (default is 25) enter it here.

Is there a limit on how many emails Interspire Email Marketer can send per day?

No. There is no restriction on how many emails that can be sent per day using Interspire Email Marketer.

If you are offering Interspire Email Marketer as an email service to your clients, you can limit the number of emails that can be sent per hour and per month. This can be done in the settings page on a global basis (all users) or on a per user basis by editing the user account.

Interspire Email Marketer tells me that my send is complete but says that it has sent to less then the total list. Why is this and what can I do?

If Interspire Email Marketer says that it has sent to less then the amount that it should have but also states that it has completed sending then some emails have been rejected from your mail server for some reason. Interspire Email Marketer will simply receive a ‘Yes I accepted the email’ or ‘No I did not accept’ message from the mail server. This means that there is no way to determine the exact reason why the message was rejected.

This could be because your host has a per hour sending limit in place to slow down all sending on the server. If this could be the case you should contact your host to see if they have a limit and what it is and then set this limit in the Interspire Email Marketer settings page so that you do not send faster then this limit and risk your emails being blocked by the server.

If this is not the case and your hosts do not have any limitations in place you should ask them to see if the mail server was down for any time whilst your send was in place. If they say that it was not down then you can request the server logs for that time frame to see if there was any errors recorded that may inform you as to what has happened.

Why do I have to continually restart my email campaigns?

The most common reason for this is that your host has set restrictions on your server so that processes are not run for over a particular length of time. This is to cover themselves so that if someone runs a malicious script it will not run forever. This limit for instance could be set to kill any process that runs for an hour.

That means if your scheduled task job takes longer than 1 hour 1 minute to finish, then the server will kill it off.

If you are sending a lot of email (eg you have 30,000 contacts), this may mean it gets killed off before all of the emails get sent.

Interspire Email Marketer should handle this and automatically pick up from where it left off (it will not start again from scratch and re-send to the first X contacts).

It does not mean PHP will run 24/7. When the scheduled task runs it will:

  • see if any emails need to be sent.
  • see if any autoresponders need to be sent.
  • perform any automatic bounce processing that needs to be done.

If there are no email campaigns to be sent, that step is skipped. Same for autoresponders and bounce processing.

So it will only run long enough to perform everything it needs and nothing else.

It also handles overlapping tasks (eg you send to 30,000 contacts and it takes longer than 1 hour to run, when the second scheduled task runs it will not start the same email campaign send again).

What is multipart sending and why should I do this?

When you are sending an email you can choose to send it as “Multipart”.

What this means is that Interspire Email Marketer will take both the HTML version and the Text version of your email and bundle it into the one email. When your contact receives this email their email client (such as Outlook, Gmail, Hotmail) will then read the email and display the most appropriate email for them.

If you do not allow your contacts to choose their subscription type when they subscribe and they are signed up as HTML then you should send your emails as multipart. The reason for this is that if your contacts log into a webmail client for instance, they will be shown the text version of your email. However if they then view their email in a client such as Microsoft’s Outlook they will see the HTML version of this email.

If your contacts are given the choice between Text and HTML when they subscribe then you should still write both types of your email (Text and HTML) but not send using multipart. Interspire Email Marketer will then look at what your contact has elected to receive and send them an email of that type.

Can Interspire Email Marketer send one email to multiple lists?

Interspire Email Marketer can send your email to multiple/all lists at once. It also takes care of making sure duplicate copies of the email are not sent to the same person if they are subscribed to multiple lists.

When prompted to select your contact list, simply hold down the CTRL key and select the lists you wish to send to.

Why do my images not get embedded when I send a test email?

When you send a test email to yourself you the images do not get embedded.

This only happens when you send a proper email to a contact list and select Embed Images.

Can I add my name to my sends so that email clients will display 'My Name <[email protected]>' ?

Yes you can. When you send an email campaign or create a new autoresponder you can set up your name so that your emails will display as 'My Name <[email protected]>'

This is done by setting the ‘Send To First Name’ and ‘ Send To Last Name’

What’s the difference between using SMTP server and a PHP mail command?

The main difference with these is that if you are using SMTP there are less connections to the server.

If you are sending via cron you will find that there is a slight increase in speed as there is a smaller overhead in regards to the connections.

However, if your mail server is optimized in anyway then the server that is set up better will obviously increase your speed of sending.

You should talk to your host to find out if mail server optimization is a service that they offer as the mail server is where your send speed will bottleneck.