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Started by Ninho, August 12, 2009, 12:24:04 AM
Quote from: broquea on August 12, 2009, 12:26:10 AMProbably easier, is that your ISP block port 25 on ipv4 only. If you have a tunnel with us, try the new NMAP feature in the broker's webUI and have it scan an IP allocated to your tunnel, you are trying to bind an MTA to.
$ORIGIN mydomain.tld IN MX 5 ipv6mx.mydomain.tld. IN MX 10 ipv4mx.someotherdomain.tld. ;backup IPv4 MX that can do SMTP over port 25ipv6mx IN AAAA 2001:DB8::123
Quote from: jimb on August 12, 2009, 02:29:53 AMMy guess is that you are talking about doing something like this:
QuoteI think this scenario will work. It should work like this:IPv6 capable mail servers will deliver directly to the higher priority MX (ipv6 one).IPv4 only mail servers will fail to find an A record associated with the IPv6 MX, and move to the next lower priority MX record.It works when I tested it on a IPv4 only sendmail box with just such a config. I had the IPv6 set as the higher prio MX, and the IPv4 set as lower. It skipped the IPv6 MX and moved right on to the IPv4.You could always give it a try on a test (sub)domain to see how it works with a variety of mail servers on the internet. :PEDIT: I also tested it by sending mail from gmail to the test domain set up in this fashion, and it worked (delivered it via IPv4 to the backup MX ... apparently gmail SMTP servers don't do IPv6 yet).