greylisting and email retries

[ceeb]

I've experienced a couple of email greylist problems - the email recipient's server temporarily rejects the email and waits for it to be sent again.

In all cases, I've received an email from the Dathorn server saying that it's going to retry. Unfortunately, this arrives around 3-4 days after I sent the original message so most greylist systems still would reject any message sent after that time.

How frequently will the Dathorn servers attempt to resend a rejected email?

[AndrewT]

It varies greatly depending on server loads and the amount of e-mails that are in the mail queue.

Greylisting is a very poor method of spam protection.

[djn]

I've just had the same kind of problem with mail originating from cpanel17. From what I can tell from the partial logs at the destination server (I have admittedly not very much experience at reading mail logs) it seems that the sending server, after being rejected for 5 minutes, tried the secondary MX just 2 minutes later and then gave up?
BTW, is 69.93.111.59 the IP from which all cpanel17 mail goes out? I think I'll just have to whitelist my customer (the recipient is a government and I don't think I can talk them out of this stuff).

[AndrewT]

That is the correct IP for cpanel17.