Transparent hijacking of SMTP submission...

Jean-Francois Mezei jfmezei_nanog at vaxination.ca
Sat Nov 29 17:26:59 UTC 2014


On 14-11-29 11:07, Sander Steffann wrote:

> I am so glad that our Dutch net neutrality laws state that "providers of Internet access services may not hinder or delay any services or applications on the Internet" (unless [...], but those exceptions make sense)


However, in the case of SMTP, due to the amount of spam, most ISPs break
"network neutrality" by blocking outbound port 25 for instance, and
their SMTP servers will block much incoming emails (spam).  However,
SMTP is a layer or two above the network. But blocking port 25 is at the
network level.

I have seen wi-fi systems where you ask to connect to 20.21.22.23 port
25, and you get connected to 50.51.52.53 port 25. (the ISPs own SMTP
server).  I would rather they just block it than redirect you without
warning to an SMTP server of their own where they can look and your
outbound email, pretend to acccept it, and never deliver it.





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