3 Jan
2017
3 Jan
'17
3:31 p.m.
We are seeing problems with greylisting in mails coming from UPC mailservers. After receiving our "451 Greylisting" response, we never see a retry of the mail again. The sender does not receive an NDR. We have seen this behaviour from the servers at 84.116.36.xxx. Other servers for example the ones in the range 62.179.121.xxx are retrying correctly.
Anybody from UPC here to help sort this out or is anyone else seeing the same problem or is no one using greylisting anymore these days?
We have seen the very same problem with the very same ISP...
We turned off greylisting for now.