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I'm wondering how you would go about pausing an ip address to a remote domain based on a string received. I received an error code from yahoo and my IP was blocked for a long time. I was told it was because it I didn't respect their deferral code and I needed to pause sending email to them if I ever received one of a handful of deferral codes again. However, I have no clue how to do this.

I'm using Exim4, but I wouldn't be opposed to using something else like qmail or postfix if Exim4 can't do this.

Thank You, William

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I think this 'pausing' you describe is basically built into the SMTP specification. Therefore, Exim should handle deferrals from remote SMTP servers as per the spec and an out-of-the-box configuration shouldn't get your IP banned from anywhere. I'm guessing there's thousands of Exim mailservers out there that do obey the deferral spec and therefore don't cause and issue.

All of this leads me to conclude that either (a) there's something in your config that changes how aggressively exim attempts redelivery, or (b) Yahoo's doing something screwy.

You've not posted any details from your config, so it's difficult to be a bit more specific. Take a look through section 33 of the documentation which talks a bit more about how to configure retry rules for hosts. The granularity is useful here in case you've got a host that is really strict about long deferrals.

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It sounds like Yahoo is greylisting your email server and your retry interval is too short. Take a look at the retry interval in Exim and make sure that it's set appropriately.

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