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Send limit in smarter mail
Question asked by Vince - 1/12/2022 at 4:14 PM
Answered
We were using another email server prior to moving to smartermail. the other server had a setting that could limit the amount of emails that could be sent by an account. This prevented our servers spool from either filling up with spam messages trying to be delivered and preventing us from getting blacklisted.

an account on our smartermail server was compromised and was trying to send out thousands of emails. We didn't notice there was a problem until a client complained about not receiving email. When we looked at the spool it had 80,000 emails in it. This clogged up the server and delayed email from being send and or delivered. We do have the settings on each account set do delay if over 100 messages and hour.  I thought this would protect us from being blacklisted. It seems that it has, but it doesnt stop the spool from getting full of messages it only delays sending out mail, but the spool continues to fill with the spam message.
Is there a way to prevent this from happening again?
like some sort of send limit per day set on each account. or some other solution that would prevent the spool from getting full of spam like in our situation described above?

Thank You

8 Replies

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Zach Sylvester Replied
Employee Post
Hello Vince, 

Thank you for reaching out to the community. I would recommend changing the action from delay to reject. If your clients are regularly sending over 100 messages an hour maybe change the limit to 300 then they won't notice it. A spammer however would. Please let me know if you have any other questions. 

Kind Regards, 
Zach Sylvester
Technical Support Specialist
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
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Vince Replied
Hi Zach,

OK, I changed it to reject, and tested. 
I changed the send limit to 3 and reject on a test account .

I logged into webmail and sent over 3 emails, they all showed as sent. I only received 3 in the destination address, but 1 hour later the other 3 were received even though I have marked as reject. 
I also tried sending more than 3 with outlook, they also show as sent in outlook. but again I only received 3, but received 3 more an hour after.

Both outlook and webmail don't indicate that a send limit was reached, they appeared to continue to send.

Vince
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Emily Ward Replied
Employee Post
Hi Vince,

I actually experienced this same thing the other day when testing the Reject action. I submitted the issue to support for troubleshooting. I added a reference to this post in my ticket as well.
Emily Ward
Customer Relations and Partner Specialist
SmarterTools Inc.
(877) 357-6278
www.smartertools.com
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Vince Replied
Hi Emily, 
Yes, I tried it again and it is definitely delaying not rejecting.

Zach, We did end up getting blacklisted from some servers. what a nightmare trying to get de-listed...
Is there not a way to limit the overall send limit for an account per day, rather than a per hour setting only. Using a per day setting with a diff. mail server we were using has prevented us getting blacklisted over the last 6 years. Before we put that limit in place we were blacklisted a few times in a year. As I am moving more users over to to SmarterMail I feel the risk is much higher using a per hour approach.
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JerseyConnect Team Replied
You can also setup events to trigger when a user gets throttled or when the spool count gets too high. This way you know to check the account and/or the messages in the spool and see if something has been compromised.
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Vince Replied
Hi JerseyConnect Team,

Thank you for the suggestion.
I have implemented what you suggested. I hope this works out.

I still think a total mail sent limit for a day is a better solution. Especially if someone says they only send out 30 emails a day. 
We used to set a limit of 300 a day with other product, this has kept us off black lists for years even when an account gets compromised. There would be no way to limit that with a per hour limit. Especially if it happens in the middle of the night when no one is watching. The queue could get full/and or send out whatever limit set per hour.

Vince
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echoDreamz Replied
This is one of the reasons we have our own spool proc app that handles sending limits and more, easier for us to do overrides for a specific user or domain as well as the system trains itself to each users avg normals. 
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Emily Ward Replied
Employee Post Marked As Answer
Hi All,

I heard back today about the issue with the throttling action "Reject" not rejecting. This is actually working as designed. 

If the EML for any message has already reached the spool before the throttling action is engaged, then those messages WON'T get rejected. However, once the throttling action is implemented any additional messages WILL be rejected. So if you have a limit of 5 emails an hour and a user sends 10 emails in succession, all 10 may get through, or at least a few more messages than the limit depending on how quickly the messages are being sent. If you send 5 emails, wait a few minutes, then any additional messages would get rejected because the throttling action has been engaged at that point.
Emily Ward
Customer Relations and Partner Specialist
SmarterTools Inc.
(877) 357-6278
www.smartertools.com

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