IPv6 isn't SMTP

Wed Mar 26 15:25:38 UTC 2014

On 03/26/2014 08:05 AM, rwebb at ropeguru.com wrote:
> On Wed, 26 Mar 2014 07:45:06 -0500
>  Daniel Taylor <dtaylor at vocalabs.com> wrote:
>> On 03/25/2014 11:18 PM, John Levine wrote:
>>>> 3.  Arguing about IPv6 in the context of requirements upon SMTP 
>>>> connections is playing that uncomfortable game with
>>>> one�s own combat boots.  And not particularly productive.
>>> If you can figure out how to do effective spam filtering without
>>> looking at the IP addresses from which mail arrives, you will be in a
>>> position to make a whole lot of money.
>>>
>>> But, as always, I'm not holding my breath.
>>>
>>> R's,
>>> John
>>>
>>> PS: Note the word "effective".
>>>
>> You look at the IP, and verify forward and reverse DNS.
>>
>> IPv6 doesn't make this any harder a problem than IPv4, it just means 
>> that we're going to *have* to reject mail that comes in from IPv6 
>> addresses that don't have clean DNS.
>>
>> -- 
>> Daniel Taylor          VP Operations            Vocal Laboratories, Inc.
>> dtaylor at vocalabs.com   http://www.vocalabs.com/ (612)235-5711
>>
>>
>
> Actually, with all the discussion about ipv6 not having rDNS, in most 
> cases, would that not make things easier? So those that want to run 
> email servers SHOULD be on ISP's that allow for rDNS configuration for 
> IPv6. There should be some vetting in the process by the ISP, maybe, 
> before allowing this. So in essence, if you are a legitimate email 
> host, you will have rDNS configured on IPv6 for your server. Again, as 
> others have stated, rDNS should NOT be the only deciding factor in 
> whether or not an email is legit. No rDNS, or havinf rDNS, should have 
> some weight assigned to it for the overall evaluation of the sender.
>
> Robert
If you can't get rDNS on a mail host from your ISP, I'd say you are on 
the wrong ISP if you want to run your own mail server.

This goes for IPv6 and IPv4 equally.

-- 
Daniel Taylor          VP Operations            Vocal Laboratories, Inc.
dtaylor at vocalabs.com   http://www.vocalabs.com/            (612)235-5711