why IPv6 isn't ready for prime time, SMTP edition

Brielle Bruns bruns at 2mbit.com
Tue Mar 25 20:57:15 UTC 2014

On 3/25/14, 11:56 AM, John Levine wrote:
> I think this would be a good time to fix your mail server setup.
> You're never going to get much v6 mail delivered without rDNS, because
> receivers won't even look at your mail to see if it's authenticated.
> CenturyLink is reasonably technically clued so it shouldn't be
> impossible to get them to fix it.

Nothing wrong with my mail server setup, except the lack of RDNS. 
Lacking reverse should be one of many things to consider with rejecting 
e-mails, but should not be the only condition.

That would be like outright refusing mail unless it had both SPF and 
DKIM on every single message.

Sure, great in theory, does not work in reality and will result in lost 
mail from legit sources.

Already spoken to CenturyLink about RDNS for ipv6 - won't have rdns 
until native IPv6.  Currently, IPv6 seems to be delivered for those who 
want it, via 6rd.

And, frankly, I'm not going to get in a fight with CenturyLink over IPv6 
RDNS, considering that I am thankful that they are even offering IPv6 
when other large providers aren't even trying to do so to their 
residential and small business customers.

It is very easy for some to forget that not everyone has a gigabit fiber 
connection to their homes with ARIN assigned IPv4/IPv6 blocks announced 
over BGP.  Some of us actually have to make do with (sometimes very) 
limited budgets and what the market is offering us and has made available.

Brielle Bruns
The Summit Open Source Development Group
http://www.sosdg.org    /     http://www.ahbl.org

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