On 2021-01-25 01:22, P. Ik. wrote:
Dec 29 06:48:27 mail postfix/qmgr[108]: 6A158635: from=<i...@fbi.gov>, size=2222, nrcpt=20 (queue active) Dec 29 06:48:27 mail postfix/smtpd[4467]: B033063B: client=unknown[172.17.0.1] Dec 29 06:48:27 mail postfix/smtpd[4470]: C3D6F63C: client=unknown[172.17.0.1] Dec 29 06:48:27 mail postfix/smtp[4479]: 0D42C630: to=<britneyba...@aol.com>, relay=smtp.gmail.com [1][64.233.191.108]:587, delay=3.9, delays=3.1/0.17/0.3/0.36, dsn=2.0.0, status=sent (250 2.0.0 OK 1609224507 x5sm28764963ilm.22 - gsmtp)
/etc/postfix/main.cf: proxy_interfaces = 1.2.3.4 (the proxy/NAT external network address) you miss this :)