James On Fri, Jan 23, 2015, at 07:25 AM, James B. Byrne wrote: > To the best of my ability to recall the mail was coming from/through > servers in the user's own domain, which is a quite large > multi-national. We never saw this problem with any other user of > theirs. Of course, having white listed the domain we are unlikely to > ever again. > > The only thing that we could discover that marked this user out from > all the rest was that their messages which exhibited this problem all > claimed to be sent from their BlackBerry. When the same user had sent > messages from some other location or device, presumably their office > workstation, they never had this problem when grey-listed. At least, > none that we could detect from the logs. > > They were an infrequent correspondent which is why they were > repeatedly grey-listed.
Ok, thanks for the 'case'. So the question isn't just what the average delay length is, but also which ISPs are resending the mails from different IPs. Obvious guess is 'the big/popular ones'. They're usually not the problem, at least not from a policy perspective. I don't know, and doubt, that you can easily get complete lists of the IPs the big ISPs to whitelist them in any case. Bit of a flip of the coin re: 'acceptable losses'. I'm leaning to turning it off for now and living with the consequences of increase in spam load. Roger
