[AusNOG] [SHAME] spamrats.com

[Mark Smith]

----- Original Message -----
> From: Lloyd Wood <lloyd.wood at yahoo.co.uk>
> To: Anand Kumria <akumria at acm.org>
> Cc: "ausnog at lists.ausnog.net" <ausnog at lists.ausnog.net>
> Sent: Thursday, 10 January 2013 9:58 PM
> Subject: Re: [AusNOG] [SHAME] spamrats.com
> 
> MUST and SHOULD are defined in the later RFC2119.
> 
> RFC793 doesn't use them either.
> 

Because RFC2119 wasn't defined at that time.

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

RFC2119 is still a BCP, and is still in standards track RFC boilerplate.

> 
>>> 
>>> 
>>>  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  are very outdated.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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