On 20/09/2018 13.05, James Knott wrote:
On 09/20/2018 12:50 PM, Carlos E. R. wrote:
I find blocking 25 intrusive on my freedom.
You find it intrusive on your freedom to do something you shouldn't be doing?
I'm not doing anything I shouldn't.
SMTP was created way back in the dark ages, when people used terminals to connect to computers and programs on that computer to read/write mail. Back then, SMPT was used to transfer mail between computers. There was no concept of email clients back then. When those clients started appearing, they used POP and SMTP to provide email to personal computers. That situation resulted in port 25 being used for spam, as there was nothing to stop that. Then ISPs stopped passing port 25 on to other servers, just to block that spam. As mentioned, there are other ports for sending email from clients and they should be used. If your ISP doesn't support that, then they are part of the problem.
Well, Telefónica is apparently managing to block spam without blocking 25. For instance, by requesting authorization on connect to 25. Everybody does that, even gmail.
BTW, I recently started re-reading "The Cuckoo's Egg" about a security attack that was enabled by a flaw in the way Emacs handled sending email. This let the attackers bypass normal system security to get access to the system. I first read it almost 30 years ago. It's a good read.
:-) When I developed software, security was not a concern. Oh, those were the days... ;-p -- Cheers / Saludos, Carlos E. R. (from openSUSE 15.0 (Legolas))