Coming 50+ mails at the same time problem

[mehmethyeni]

Hi,

We have set up ironport C170 email appliance to a customer. Everything seems fine until morning. They called me and said a single e-mail account (gmail) have sent 60 mails to a client instantaneously and all of them passed through ironport. So how could we solve this problem ? Is there any restriction method to block the same mails if  a client receives more than 1 or any number that we can assign?

Thank you,

Mehmet.

[Bob Fayne]

You can set up a rate limit only by total number of recipients. You could set a rule that says *.google.com can only send to x number of recipients per hour but that impacts all recipients, not just one.

60 emails all at once could be accidental but without more information I would check to make sure that there was not some sort of routing or transport problem that caused a backlog and when it cleared up all the waiting email was delivered at once.

[mehmethyeni]

Hello Bob,

Thanks for the reply. I guess I understand the problem but don't know how to solve it. After some analysis in the message tracking ı found that source IP of the mails seems the default gateway of ironport. Actually, I was shocked. How can it be? ı think a special destination NAT could cause this problem. When I said this situation to the customer, they said that did not make any NAT config like this. Do you recommend me something to implement?

Thanks,