On Monday 13 February 2017 18.09, Richard Clayton wrote:
In message <201702131743.10508.peter@hk.ipsec.se>, peter h <peter@hk.ipsec.se> writes
The very simplest thing to do is make sure any outbound smtp is relaye through the ISP's mailrelays, where spam could be detected and subsequently blocked.
this is very unpopular with legitimate businesses who wish to be fully in control of their email sending destiny -- and ISPs generally do not wish to discourage the people who cause no trouble and pay their bills regularly and on time
so although "port 25 blocking" is a M3AAWG Best Practice it has not been widely adopted with the main (but not only) exception being the large consumer ISPs in the US (ISPs in Europe have, for historical reasons, had a significant number of business customers mixed in with pure consumers and that has made the difference)
There is not any req that all customers always should be forced to use ISP relays, the default behaviour might be to use ISP relays, and to have DHCP given address. But for an extra service one could obtain a fixed address, and as extra service, use port 25. The main point is to have those "unaware" users, whos computers might be stolen, prevented. They won't notice, and they don't get harmed. Spam from a fixed ip or range is much easier to detact and correct then spam from any box that happens to get an DHCP lease. Flexibility and service is the keyword here. Also, to have a AUP that gives the ISP right to disconnect or block offenders is importent, and also that the customer has right to service. Any aggreement is twofold, both rights and obligations, like in society in general. I'm glad that spam is recignised as the problem it is and hope a renewed activity to claim back the bandwitdh and storage space the spammer has taken from us. Yours -- Peter Håkanson There's never money to do it right, but always money to do it again ... and again ... and again ... and again. ( Det är billigare att göra rätt. Det är dyrt att laga fel. )