SMTP quota

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Overview

DreamHost limits the amount of outgoing mail from its servers in an effort to fight Unsolicited Bulk Email (UBE) also known as SPAM. This helps to prevent DreamHost servers from being black/gray listed and added to blocklists, which in turns prevents email from being delivered on time. In return, your email service is more reliable and stable.

When you exceed this outgoing quota limit, you will get a rejection notice that says the email failed to send due to "Policy Rejection- Quota Exceeded." This means that you have exceeded or attempted to exceed your mail sending limit for that particular account.

This article details the SMTP quota limits (depending on how you're sending email) along with examples of what may cause those limits to be hit.

Default sending limits/quotas

Sending method Recipient per hour Max recipient per message Max message size
SMTP authentication in an email client 100 100 40MB (encoded)
SMTP authentication in webmail 100 100 7MB
SMTP authentication in a webform 100 100 40MB (encoded)
FTP & Shell users on shared servers. Sending using PHP/CGI scripts. 200 40 40MB (encoded)
FTP & Shell users on VPS or Dedicated servers. Sending using PHP/CGI scripts. Unlimited Unlimited 40MB (encoded)
Announcement Lists Unlimited Unlimited 40MB (encoded)
Discussion Lists Unlimited Unlimited 40MB (encoded)
Important icon.png Important: The limits above are based on the number of RECIPIENTS, not the number of messages. For example, a single email message with 5 recipients would count as 5 towards your sending limit. All recipients in the TO, CC, and BCC fields are counted.


Incoming message limitations

  • The sending limits mentioned above do NOT apply to incoming messages. Just for completeness, here are two incoming message limitations:
  • Maximum message size: This is set to 40MB. Incoming messages over 40MB are bounced.
  • The amount of disk space you've allocated to your mailbox: if your mailbox fills up, it bounces incoming messages. You may not even be able to delete any messages because the server needs some free space in order to work. So, try to avoid allowing your mailboxes fill up. See the Disk Usage Warning article for more information on setting the "Limit total disk usage" and Inbox Archiver article for how to configure "Email me daily" warning messages for your accounts.
  • DreamHost recommends allocating at least 100MB for each mailbox. Attachments in a single email can take up several MB. So just a few large message can fill your inbox.
  • DreamHost recommends enabling the "Email me daily" warning messages option for your accounts. These notifications help you to avoid hitting your disk quota limit.
  • If you have the "Save removed messages" option enabled (which is the default option), those saved messages can eat up your disk space without you ever seeing them. Make sure that you've subscribed to the old-messages folder (or whatever you've configured it to be) so you know what's in there.

Examples and explanations of limits

Examples of how the limits are implemented

How the message is sent Message and Recipients Outcome
SMTP
Single message with 100 recipients.
  • You reach the maximum sending limit for that hour.
  • After one hour, you can attempt to send more messages.
SMTP
5 messages with 5 recipients each during one hour.
The system counts this as 25 recipients during that hour.
SMTP
100 messages with a single recipient each.
You reach the maximum sending limit for that hour.
SMTP
Single message to 50 recipients, and then within that same hour try to send another message with 55 recipients.
  • The second message FAILS and your account is blocked because it exceeds your sending limit.
  • You must wait for that hour to elapse (from the time you send the first message) before you can attempt to resend the message which could not be sent during the last hour.

What happens when you hit the limits

Once you have reached your hourly sending limit, any message that you attempt to send that exceeds your sending limit causes your account to be blocked immediately. Those messages that exceeded, or attempted to exceed, your sending limit are NOT sent and fail with a "Policy Rejection- Quota Exceeded" error message. Those unsent messages typically remain in your email client's "outbox" so that you can attempt to resend them later.

Note2 icon.png Note: If you are blocked for exceeding quota, the block will remain in place until at least one hour has passed during which time there have been no further attempts to send mail from the account.


Some email clients (most notably Outlook) will try to send anything in the "outbox" at regular intervals, or at every attempt to send. To have the quota lifted as soon as possible, make sure to remove any message from the outbox, and wait at least an hour before attempting to send again.

However, the mail servers AUTOMATICALLY unblock/reset your account one hour after the first message that was sent. There is no need to contact support when this happens.

Also, if a message that has been successfully sent to a recipient bounces back to you for various reasons, it still counts towards your sending limit. They are not deducted from your sending limit.

Important icon.png Important: Accounts that are blocked repeatedly for attempting to exceed the sending limit are blocked permanently by the system. If this happens to your account, you are required to contact technical support for assistance in order to have your account unblocked. In your support request, please include your email username and email address.


Examples of what can cause you to hit the limits

  • If you have an account set as a forward to any email sent to an another address, those forwarded messages also count towards your sending limit.
  • If you have Keyword Filters on an account that are set to forward any email to another address, those forwarded messages also count towards your sending limit.
  • Auto-responder messages also count toward that account's hourly sending limit.
  • Multiple websites hosted under the same FTP/Shell account that send email all count towards that FTP/Shell account's sending limit.
  • If you use Cron jobs to send email, they count towards the shell account's hourly sending limit. Cron job completion/error notification emails also count.
  • Cron jobs and other scripts/CGI processes that use authenticated SMTP to send email messages are restricted to the sending limit of the address that they use for authentication.
  • Email limits are per email address. This does not mean you can "spread" your bulk/mass email across several email addresses. If you need to send more than 1–2 emails every minute, then you should review the DreamHost anti-spam/bulkmail policy.

Viruses, spyware, and adware

Viruses, spyware, and adware can infect your computer and send email to everyone in your clients address book. Or, they may just use your email account to send out its spam messages.

The sending limits help to curtail the amount of damage done by these breaches. If you know that you have not exceeded your sending limits and receive the error "Policy Rejection- Quota Exceeded", contact DreamHost support. When contacting support, make sure to add the email address/username that is being blocked. Support can then review the mail logs to determine what has happened.

It’s possible that email has been sent through your account without your knowledge. If that happens, you must run virus, spyware, and adware scans to clean up your computer.

Announcement Lists

If you need to routinely send email to a large number of recipients, DreamHost strongly recommends you use an Announcement List. You can set this up in your panel on the (Panel > ‘Mail’ > ‘Announce Lists’) page.

The Announcement List service makes it easy to deal with large groups of subscribers as you do not have to worry about sending limits or hitting quotas. The Announcement List service manages the opt-in confirmations for you as well which complies with Anti-Spam policies. For further information about this service, please visit the following article:

Log output

If DreamHost support sends you the output from your logs for your verification, here's how to interpret them.

Example:

-------1------- ------2--------- ---------3--------- ---------4------------- -----------5------------- 
Jan  2 07:40:47 throttle=new(a), host=99.128.162.62, from=user@example.com, to=family@example.com, 


------6-------- ------7------- ---------8--------- ----------------9--------------
count=1/100(1), rcpt=1/100(1), threshold=0%|0%|0%, sasl_username=user@example.com

The fields are as follows:

  1. Date and time
  2. Throttle status code (see details below)
  3. Host IP address of mail client (Webmail shows up as 127.0.0.1)
  4. "From" address
  5. "To" address (can also be from CC or BCC field)
  6. Message count – number of messages during this period / period limit (messages can have multiple recipients)
  7. Recipient count – total during this period / period limit
  8. Threshold info (percentages) – the 3rd one is the only relevant one
  9. "sasl_username" – account used for SMTP authentication (Webmail does not show this field)
Ignore numbers or letters in parenthesis in the log output.
Throttle status codes and meanings
new = Initial throttle start (first message sent beginning a new period).
clear = Throttle restarted (first message sent beginning a new period).
update = Update to throttle (current period in process).
abuse = Throttle exceeded. Account blocked until throttle period expires. No messages sent. See examples above.

See also