On Thu, Dec 03, 2020 at 11:22:29PM -0200, Viktor Dukhovni wrote: > The only possible explanations are: > > - Your resolver erroneously reported NODATA for IPv4 > - The authoritative nameservers reported NODATA for IPv4 > - Neither of us was able to spot a subtle bug > > To distinguish between these, it would be helpful if you > set: > > debug_peer_list = another-example-com.mail.protection.outlook.com > debug_peer_level = 1
Unfortunately, it looks like "debug_peer_list" kicks in only after connection establishment, and produces verbose logging of the SMTP dialogue, but does not cover DNS resolution. For the latter, you'd need a dedicated transport, with "smtp -v" in master.cf. main.cf: indexed = ${default_database_type}:${config_directory}/ transport_maps = ${indexed}transport transport: another-example.com debug-smtp master.cf: # Just like "smtp", but with "-v" debug-smtp unix ... smtp -v -- Viktor.