On Sun, Mar 4, 2018 at 12:41 PM, Russell Senior <[email protected]> wrote: > What is the purpose of the message? Maybe you can send a message > instead to a central server (e.g. via a UDP packet to a particular > port), do some validation on that message (perhaps with public key > cryptography) and have the central server send the email for you?
If the target audience is likely to filter outbound traffic aggressively, then using tcp port 80 or 443 is maybe least likely to be molested. > > On Sun, Mar 4, 2018 at 12:35 PM, <[email protected]> wrote: >> Thanks John. You've kind of summed up what I know -- at least I know I have >> it right. >> >> Need to think of how to make it work as you said, without burdening any >> non-technical people with too much work. >> >> >> On 2018-03-04 11:51, John Meissen wrote: >>> >>> Sending email is easy. The device simply connects to the MX host for the >>> destination (specified in the destination domain's DNS records) and hands >>> off >>> the email. >>> >>> The problems arise when ISPs block outgoing connections to port 25 (to >>> mitigate >>> spam from compromised systems inside their network) and when mail servers >>> block >>> incoming connections from sources such as dynamic IP addresses, typically >>> home >>> Internet service, etc. >>> >>> The only way around those issues is to route the email through a trusted >>> source, such as authenticating with the ISP's mail server or the product >>> manufacturer's hosted system. >>> >>> [email protected] said: >>>> >>>> >>>> If I sold you an IoT device that sent email, how would you want it to do >>>> so? >>>> >>>> I'm looking for the ideal compromise between minimum work programming >>>> the thing, reliably getting emails to people who need them (i.e., not >>>> getting caught in spam traps), and not asking the IT people at the >>>> organization where the thing is installed to poke Great Big Holes in >>>> their firewalls. >>>> >>>> The command: >>>> >>>> echo I can send mail from the Linux command line! | mail -s "This is a >>>> mail message" -t [email protected] >>>> >>>> works when the underlying mail system is configured to claim that it's >>>> sending from [email protected] -- but (A) if I send it to >>>> [email protected] it gets caught in a spam trap at a low enough >>>> level that I can't even find it in my filters, and (B) it just seems too >>>> easy. >>>> >>>> This is all with the heirloom-mailx package in Ubuntu 16.04. >>>> >>> >>> >>> _______________________________________________ >>> PLUG mailing list >>> [email protected] >>> http://lists.pdxlinux.org/mailman/listinfo/plug >> >> >> _______________________________________________ >> PLUG mailing list >> [email protected] >> http://lists.pdxlinux.org/mailman/listinfo/plug _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
