They don't. Addresses in the headers are usually used as envelope recipients (RCPT TO:) by the sending system. The receiving system only looks at the envelope. It doesn't care what's in the To: or CC: headers.
Sent from my iPhone > On Jan 13, 2017, at 12:58 PM, Fazzina, Angelo <angelo.fazz...@uconn.edu> > wrote: > > Sorry for my lack of indepth knowledge of postfix. > Is there a link to read on how email addresses in CC: field get processed by > postfix? > Googling has not help so far. > -ALF > > -Angelo Fazzina > Operating Systems Programmer / Analyst > University of Connecticut, UITS, SSG, Server Systems > 860-486-9075 > > > -----Original Message----- > From: owner-postfix-us...@postfix.org > [mailto:owner-postfix-us...@postfix.org] On Behalf Of Wietse Venema > Sent: Friday, January 13, 2017 3:55 PM > To: Postfix users <postfix-users@postfix.org> > Subject: Re: need help finding a missing email. thanks for looking > > Fazzina, Angelo: >> I have this email that had 2 users in the CC field, and only one got the >> email. >> Anyone see any obvious reason why ? >> mehgan.willi...@uconn.edu did NOT get the email. >> >> My guess is postfix messed up reading the CC field ? > > Postfix does not deliver to CC headers. Instead, recipients are > specified with the RCPT TO command (in SMTP). > >> Jan 2 14:38:40 mta2 postfix/smtpd[27910]: 30B066FA: >> client=spam2.uits.uconn.edu[137.99.25.229] >> Jan 2 14:38:40 mta2 postfix/cleanup[27951]: 30B066FA: warning: header >> Subject: Re: introductions from spam2.uits.uconn.edu[137.99.25.229]; >> from=<s...@supporttaskforce.com> to=<michael.zac....@uconn.edu> proto=ESMTP >> helo=<spam2.uits.uconn.edu> >> Jan 2 14:38:40 mta2 postfix/cleanup[27951]: 30B066FA: >> message-id=<931694ed-c8d9-488c-9868-a675c37be...@supporttaskforce.com> >> Jan 2 14:38:40 mta2 postfix/qmgr[7452]: 30B066FA: >> from=<s...@supporttaskforce.com>, size=263848, nrcpt=1 (queue active) > > The above message has ONE RECIPIENT (specified with RCPT TO). > >> Jan 2 14:38:43 mta2 postfix/smtp[26955]: 30B066FA: >> to=<mjz0....@uconn.mail.onmicrosoft.com>, >> orig_to=<michael.zac....@uconn.edu>, >> relay=uconn-mail-onmicrosoft-com.mail.protection.outlook.com[207.46.163.247]:25, >> delay=3.1, delays=0.02/0/0.27/2.8, dsn=2.6.0, >> status=sent (250 2.6.0 >> <931694ed-c8d9-488c-9868-a675c37be...@supporttaskforce.com> >> [InternalId=102069897791116, >> Hostname=BLUPR0501MB898.namprd05.prod.outlook.com] 271315 bytes in 1.201, >> 220.548 KB/sec Queued mail for delivery) >> Jan 2 14:38:43 mta2 postfix/qmgr[7452]: 30B066FA: removed > > Wietse
