Outgoing Email Limits

#1

Hi all,

I’m Relja from Novi Sad (Serbia) - first post here. Did the search and googling - didn’t help. So, a few questions (nothing urgent). I need to send mailing lists using a custom-built application (with other functions, emails are sent to clients when needed).

People would sign up to a website (creating an account, with a registration/email confirmation link sent to their email when opening the account). Then pay for services and have tutoring times and any re-schedules information sent to their email (along with notifications on the website).

Questions:

Any links with tutorials, or suggested googling terms are more than welcome - not expecting to be spoon fed.

  1. I read 300 emails per hour limit. My question is: how is this limit calculated?
    That is, should I make sure the application keeps track of the number of sent emails in the past 60 minutes and as soon as that is below 300, it can send more (up to a total of 300)? Or is the counter reset at each full hour? In which case the app would have to take that into consideration.

  2. Is there some API interface/function to get the current sent mail per hour count?
    So the application would check that before sending any emails, not relying (solely) on its own counting.

  3. Is it possible to use a service like SendGrid alongside MXroute, for larger mailing lists. I see they have a custom DKIM DNS entries if using it alongside another service (haven’t tested yet though).

P.S. This is my current setup for MXroute email account(s), it seems to be working fine, but any corrections are welcome:

#2

Happy to answer these :slight_smile:

  1. Right now we have two filter servers running in DNS round robin (not true round robin, not even distribution). Each filter server is set to bounce emails back to the sender if that sender has exceeded 300 emails in the current hour on that filter server. This means the true limit is likely higher as 300 sequential emails going out through one filter is unlikely, but you should plan for 300. Future iterations may be more consistent, but our intention is not to have customers pushing the limit to the point that these specifics are relevant to them.

  2. Currently there is not.

  3. Sure, just add them to your SPF record.

#6

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#3

Thank you very much for the fast reply. Just to clarify the 3rd point:

I’d be replacing MXroute SPF (and DKIM) records?

For incoming email, I’d still use MXroute incoming mail server, while for sending email, from mail clients and applications, I’d need to set up SendGrid mail server?

When using MXroute webmail to send emails, I’d still be sending through MXroute infrastructure (with 300 emails per hour limit)? But, if SPF and DKIM are replaced with SendGrid ones, it would not be advisory/allowed to do so, am I correct?

#4

Your SPF record would look like:

v=spf1 include:mxlogin.com include:sendgrid.net ~all

You would not replace the SPF and DKIM records - you would combine the SPF as I have shown above and you would have a DKIM record with a different DKIM selector provided to you from Sendgrid, which you would publish in DNS.

See here for more info:

It probably would be easiest to manage with Automated Security OFF.

1 Like
#5

Thank you very much.
Very nice and clear explanation (better luck than I had with SendGrid knowledge base searching and support).

Think I understand how it works now and should be able to set it up properly. :slight_smile: