Interestingly, your mail to the nanog list went to my spam folder, rather than my nanog folder (I'm using gmail or domains for my mail.) That rarely happens. On Tue, Aug 30, 2016 at 9:22 AM, Webhosting.net Admin <admin@webhosting.net> wrote:
A few of our exchange IPs get blocked intermittently, but only by ATT. Ips are clean, no issues, we’re diligent about finding and fixing these types of issues as it has a large impact.
It would be very helpful to know why the IP below got blocked so we can find and fix the problem to prevent further listing. We have a few ips in rotation and some have no issue. It’s a “blind” listing, so we only find out about it when customers complain that they getting blocked.
ff-ip4-mx-vip1.prodigy.net #<ff-ip4-mx-vip1.prodigy.net #5.3.0 smtp; 553 5.3.0 flph399 DNSBL:ATTRBL 521< 67.215.167.170 >_is_blocked.__For_ information_see_http://att.net/blocks> #SMTP#
Any info/help would be most helpful.
Many thanks,
Webhosting.net Postmaster