"Nenhum mecanismo digno de nota encontrado" ao tentar retransmitir e-mails para o Gmail usando o Postfix

Estou tentando configurar o email para encaminhar para o Gmail, usando o Postfix para retransmitir o email para smtp.gmail.com. No entanto, não consigo autenticar com smtp.gmail.com, que é um pré-requisito vital para que tudo funcione…

Os logs de correio mostram apenas:

Oct 29 15:50:14 gsnedders-1 postfix/master[6596]: daemon started -- version 2.7.1, configuration /etc/postfix
Oct 29 15:50:19 gsnedders-1 postfix/pickup[6598]: EBA1F78750: uid=1000 from=<gsnedders>
Oct 29 15:50:19 gsnedders-1 postfix/cleanup[6603]: EBA1F78750: message-id=<20111029145019.EBA1F78750@mail.gsnedders.com>
Oct 29 15:50:19 gsnedders-1 postfix/qmgr[6599]: EBA1F78750: from=<gsnedders@gsnedders.com>, size=324, nrcpt=1 (queue active)
Oct 29 15:50:19 gsnedders-1 postfix/cleanup[6603]: F2D557874F: message-id=<20111029145019.EBA1F78750@mail.gsnedders.com>
Oct 29 15:50:19 gsnedders-1 postfix/local[6605]: EBA1F78750: to=<me@gsnedders.com>, orig_to=<me>, relay=local, delay=0.04, delays=0.03/0.02/0/0, dsn=2.0.0, status=sent (forwarded as F2D557874F)
Oct 29 15:50:19 gsnedders-1 postfix/qmgr[6599]: F2D557874F: from=<gsnedders@gsnedders.com>, size=454, nrcpt=1 (queue active)
Oct 29 15:50:19 gsnedders-1 postfix/qmgr[6599]: EBA1F78750: removed
Oct 29 15:50:20 gsnedders-1 postfix/smtp[6606]: warning: SASL authentication failure: No worthy mechs found
Oct 29 15:50:20 gsnedders-1 postfix/smtp[6606]: F2D557874F: SASL authentication failed; cannot authenticate to server smtp.gmail.com[74.125.157.108]: no mechanism available

E a configuração do postfix é:

relayhost = [smtp.gmail.com]:587

smtp_use_tls = yes
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl/passwd
smtp_sasl_security_options = noanonymous

smtp_tls_eccert_file =
smtp_tls_eckey_file =
smtp_tls_security_level = may
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtpd_tls_received_header = yes
tls_random_source = dev:/dev/urandom
smtpd_tls_security_level = may

Ah-ha! A instalação do libsasl2-modulespacote resolveu o problema.

Corrida

sudo yum install cyrus-sasl cyrus-sasl-lib cyrus-sasl-plain

me ajudou no servidor Amazon AWS.

sudo yum instalar cyrus-sasl cyrus-sasl-lib cyrus-sasl-plain

funcionou para mim com a configuração de retransmissão do Gmail (CentOS 7)

Eu estava recebendo esse problema ( tail -f /var/log/mailog):

to=<usmanali@example.com>, relay=smtp.sendgrid.net[169.45.113.201]:587, delay=0.3, delays=0.05/0.07/0.16/0.02, dsn=5.0.0, status=bounced (host smtp.sendgrid.net[169.45.113.201] said: 550 Unauthenticated senders not allowed (in reply to MAIL FROM command))

Então eu mudei o arquivo /etc/postfix/main.cfdesta maneira que adicionou as seguintes linhas no final do arquivo

mtpd_sasl_local_domain = $myhostname
smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination
mailbox_size_limit = 256000000

# Sendgrid Settings
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = static:apikey:SG.YOUR_SENDGRID_KEY
smtp_sasl_security_options = noanonymous
smtp_tls_security_level = may
header_size_limit = 4096000
relayhost = [smtp.sendgrid.net]:587

Em seguida, instalando a dependência do módulo ausente do postfix usando:

sudo yum install cyrus-sasl cyrus-sasl-lib cyrus-sasl-plain

Em seguida, reiniciando o postfix

sudo systemctl restart  postfix.service

Finalmente, ele funciona no centos 7