Hello,
I have some issues with the Cyren blocklist - one recipient's server is
bouncing mails back with
550-5.7.1 This email was rejected because it violates our security policy
550 5.7.1 CYREN IP reputation determined a medium risk associated with
the sender address X.X.X.X. (in reply to DATA command)
Their website lists the IP as yellow ("Suspicious"), with an explanation
of "The IP has only recently started sending mails, and therefore still
has an Unknown reputation".
Unblocking on their website works like a charm and is effective within
minutes. The status turns green ("No Risk"), with an explanation of
"This IP address has not been used for sending Spam".
Some time ago, usually 2-3 weeks later, the status however flaps back to
"Unknown", effectively blocking mails again. I then unblock again, just
to get blocked again 2-3 weeks later.
I'd say the mail server is configured properly - PTR, A, AAAA, SPF,
DKIM, DMARC all in place. Active DNSWL (!) listing, and no other
listings anywhere. postmaster@ and abuse@ are reachable.
I have this effect on a few machines (mine and also colleagues under a
different domain, but same hoster), including some without any outgoing
mails, and one box where I'm the only user currently. Given the IP is
from a big provider's netblock, I tend to assume that actually too few
mail samples are with Cyren, and they therefore block again. Chicken and
egg problem in the end, if I can't send mails, they can't get good
samples...
Anyone has experiences with this, any way to contact them?
Thanks a lot,
Florian
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