auth between postfix and dovecot?

ミユナ (alice) alice at
Sat Apr 23 04:35:06 UTC 2022

hello experts,

I have installed postfix and dovecot in the same machine.

Their configure looks as:

service lmtp {
    unix_listener /var/spool/postfix/private/dovecot-lmtp {
      mode = 0600
      user = postfix
      group = postfix

unix_listener /var/spool/postfix/private/auth {
    mode = 0666
    user = postfix
    group = postfix

  auth_mechanisms = plain login

  !include auth-passwdfile.conf.ext

my question is:

when postfix talks to dovecot, does it require user's username/password 
for authentication? or this communication just goes without authentication?

I asked this, b/c my webmail send mail from localhost has been going 
without authentication to postifx. so i am not sure if postfix talks to 
dovecot without requiring auth too.


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