I meant Postfix probes use a sender address even when it is a local one. Example from logs:
> postfix/qmgr[20192]: 9AE7A3F56E: from=<double-bou...@mydomain.com>, > size=269, nrcpt=1 (queue active) > postfix/local[20230]: 9AE7A3F56E: to=<cont...@mydomain.com>, *relay=local*, > delay=0.02, delays=0.01/0.01/0/0, dsn=2.0.0, status=deliverable (delivers > to mailbox) чт, 11 февр. 2021 г. в 20:58, Wietse Venema <wie...@porcupine.org>: > Eugene Podshivalov: > > When reject_unverified_sender param is set and an email is sent on behalf > > of the server the double-bounce check is still performed (i.e. sent to > > itself). > > What is 'the double-bounce check'? > > Postfix probes use a sender address that does not receive email. > There is even a feature to make the probe sender time-dependent, > to limit the impact of spam. > > Wietse > > address_verify_sender_ttl (default: 0s) > The time between changes in the time-dependent portion of address > veri- > fication probe sender addresses. The time-dependent portion is > appended > to the localpart of the address specified with the > address_ver- > ify_sender parameter. This feature is ignored when the probe > sender > addresses is the null sender, i.e. the address_verify_sender > value is > empty or <>. > > Historically, the probe sender address was fixed. This has caused > such > addresses to end up on spammer mailing lists, and has > resulted in > wasted network and processing resources. > > To enable time-dependent probe sender addresses, specify a > non-zero > time value (an integral value plus an optional one-letter suffix > that > specifies the time unit). Specify a value of at least several > hours, > to avoid problems with senders that use greylisting. Avoid nice > TTL > values, to make the result less predictable. Time units are: s > (sec- > onds), m (minutes), h (hours), d (days), w (weeks). > > This feature is available in Postfix 2.9 and later. > >
