I've used it with a less than stellar success rate. Outgoing from me has gotten 2 responses out of ten sent, and I received a pm telling me an email was coming that never arrived. No idea if others have tried to contact me, of course.
The SMTP service PM uses is NOT properly configured per SMTP and BIND rules. They have been told so and don't even understand what they are doing wrong.
loki2$ host 917145-db6.losasso.com
917145-db6.losasso.com has address 104.130.114.19
loki2$ host 104.130.114.19
Host 19.114.130.104.in-addr.arpa. not found: 3(NXDOMAIN)
loki2$
No PTR RR assocciated. BIND requires it. ITU is an international treaty-level authority. It's the LAW, not just an "RFC".
With credentials
properly set up?
loki2$ host mail.roadrunner.com
mail.roadrunner.com has address 47.43.26.44
loki2$ host 47.43.26.44
44.26.43.47.in-addr.arpa domain name pointer roadrunner-com.msg.pkvw.co.charter.net.
loki2$
On any fully rules-compliant MTA, submitting IP as cannot be associated with a PTR RR will be rejected for lack of proper association to a valid MX sender, and right up-front in the "CONNECT" phase of the SMTP sequence, first few fractional seconds. NO further bandwidth, memory, storage, nor CPU-cycles required to filter possible SPAM. It's a
given once the "prime directive" of the rules have been violated.
Same is true of a great many OTHER sending servers on the 'net, sadly.
If YOUR OWN service adheres to the proper and strict rules?
The correspondent who THINKS they have sent an email to you can have those submissions rejected at "CONNECT" or "HELO", or for other SMTP protocol violations, never even REACH "DATA" phase - before the connection is dropped, never get as far as a SPAM filter, let alone you INBOX, Those truants don't even leave much trace anywhere but... in the server's logs.
You'd have to have "root" on your mail server, or at least MTA-admin privileges to even
see those logs, so "trust me..." anal-eyes ing those is a pain in the arse you do
not want.
As badly-configured submitting MTA are the rule, rather than the exception, few receiving MTA dare actually implement those rules. Which block all "botnets", and right about 90% of all spam and malware with no need of any further filtering.
See 'host.c" in the Exim MTA source code for how it works at its most elegant. My own code contributions to it ages ago were not officially adopted. All they did was add finer-granularity to the
log output, which made the log more useful, but also more verbose, so no great loss.
PM wudda guessed the "more verbose" part, yah? OTOH, it was then Exim itself + PostgreSQL that could do the statistics so I no longer had to wear-out cataract-afflicted eyeballs.
But there you have it.
Cut off the careless, block too many of those who RIDE on the careless.
PM is in good company as victim on that.
Royal St. Andrews Golf Club did it too. Back when I had a long-time member on one of my mail servers for secure use, I had to tell him to go and use Gmail for social use!
And then.. I had to use a "sloppier" server
myself to get PM's traffic...
In cometh all the G-D Chinese "we have good cheap..." spam with it, of course!
Whom else would "harvest" PM as aggressively?
