[AusNOG] [SHAME] spamrats.com

[Lloyd Wood]

MUST and SHOULD are defined in the later RFC2119.

RFC793 doesn't use them either.

And RFC2119 and 1912 are on the legacy RFC stream....


>> 
>> 
>> RFC 1912, Section 2.1 says every Internet-reachable host should have a name
>> and "Make sure your PTR and A records match" and "For every IP address,
>> there should be matching PTR record in the in-addr.arpa domain"
>> 
>> its DNS 101
> 
> Note that it is not a *MUST* requirement, nor even a *SHOULD*.
> 
> And, frankly, _depending_ upon PTR records in 2013 is just plain daft.
> 
> % host -t mx gmail.com
> gmail.com mail is handled by 30 alt3.gmail-smtp-in.l.google.com.
> gmail.com mail is handled by 40 alt4.gmail-smtp-in.l.google.com.
> gmail.com mail is handled by 20 alt2.gmail-smtp-in.l.google.com.
> gmail.com mail is handled by 5 gmail-smtp-in.l.google.com.
> gmail.com mail is handled by 10 alt1.gmail-smtp-in.l.google.com.
> 
> % host gmail-smtp-in.l.google.com.
> gmail-smtp-in.l.google.com has address 173.194.70.26
> gmail-smtp-in.l.google.com has IPv6 address 2a00:1450:4001:c02::1b
> 
> % host 173.194.70.26
> 26.70.194.173.in-addr.arpa domain name pointer fa-in-f26.1e100.net.
> 
> % host 2a00:1450:4001:c02::1b
> b.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.c.0.1.0.0.4.0.5.4.1.0.0.a.2.ip6.arpa
> domain name pointer fa-in-x1b.1e100.net.
> 
> The lack, or mismatch, between advertised name and PTR records should
> just be used as a signal to a reputation service.
> 
> A recent post from someone who works in this area (disclosure; I don't
> use their service at this time) covers the kinds of signals you'd
> generally expect to us.
> 
> http://rolandturner.com/2012/12/14/a-defensive-strategy-for-accepting-email-over-ipv6
> 
> I realise that this doesn't help the OP but I just wanted to ensure
> that people know that PTR records are a defining anti-spam mechanism
> are very outdated.
> 
> Regards,
> Anand
> 
> -- 
> “Don’t be sad because it’s over. Smile because it happened.” – Dr. Seuss
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