Milter-greylist

Hi,

Quite a few times I get greylist delays from senders that use their ISP's mail
servers and thus come out looking as a sender from:

Received: from termserv.example.ad (xxx-xxx-xx-xx.static.example.com.au
[xxx.xxx.xx.xx])

and such a message (although valid) is delayed by 16hrs.

I only added the words "example" above and "xxx", the rest is as is so the .ad
and the .com.au don't match).

How would people recommend I deal with these?

Thanks.

Michael.