[PLUG] Question for the sysops -- IoT devices and email

John Meissen john at meissen.org
Sun Mar 4 19:51:56 UTC 2018


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.

tim at wescottdesign.com 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 timwescott0 at gmail.com
> 
> works when the underlying mail system is configured to claim that it's 
> sending from tim at wescottdesign.com -- but (A) if I send it to 
> tim at wescottdesign.com 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.
> 





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