On Wed, 14 Feb 2024 18:25:03 -0800 Stephen Satchell <list@satchell.net> wrote:
On 2/14/24 4:23 PM, Tom Samplonius wrote:
The best option is what is happening right now: you can’t get new IPv4 addresses, so you have to either buy them, or use IPv6. The free market is solving the problem right now. Another solution isn’t needed.
Really? How many mail servers are up on IPv6? How many legacy mail clients can handle IPv6? How many MTA software packages can handle IPv6 today "right out of the box" without specific configuration?
Mine have been dual stack for a while (6 years? 8 years? don't exactly recall). However, I remember being enough of an early v6 adopter that it was a bit of a challenge to get IPv6 glue records set up for our DNS servers (that was long before I was brave enough to have my email servers on v6, though).
Does any IPv6 enabled ISP provide PTR records for mail servers?
We do, of course, I can't speak for others. We also sub-delegate on request. However, we are small/local and cater to small businesses.
How does Google handle mail from an IPv6 server?
I remember Google being where some of my first v6 email was coming from and going to. I would advise that if you allow your MTA to attach to all IPv6 addresses that you make sure all of them have REV PTR. Google, at least last time I looked, would deny email via IPv6 based solely on REV PTR errors. They are more forgiving over v4, but I suspect that has/had to do with more mature spam filtering considerations on v4 than v6. I once made the mistake of not having one of my secondary addresses set up with a REV PTR and Google rejected any email that came from that IP. --TimH