Re: [tlug] [slightly OT] SMTP and the internet, protocols and the internet

["Stephen J. Turnbull" <turnbull.stephen.fw@example.com>]

Christian Horn writes:

 > - the IP reverse lookup is now pointing at mail.fluxcoil.net
 > 
 > This is not convenient as all reverse lookups for the IP will
 > now bring up mail.fluxcoil.net,

What does reverse lookups, besides SMTP?  It's in the RFCs for SMTP,
but I don't know of any other protocol that specifies that reverse
lookups have to round trip.  And not even SMTP asks that forward
lookups round trip.

It's pretty common for reverse lookups of single-host domains to point
at mail.* or smtp.* because of exactly this requirement of SMTP.

 > even if these were related to other services, i.e. https.

I could see this happening, but eventually HTTPS is going to
authenticate via a certificate signed by some verification authority,
and at that point you just need the certificate to be valid for any
domains that anyone can find that resolve to that IP and might be used
to get to your IP.

 > So it's basically back to my original issue: a provider has setup
 > rules asking me to publish my data, only then he will accept mails
 > from me.

Can't help you with that.  I don't see why they think it's a great
idea.  I don't see what problem having a physical location for an
email admin solves for them.  Are they planning to send the gendarmes
to arrest you there?

Maybe whoever enforces GDPR where you are can help.

Steve