main.cf

# Basic Postfix configuration
compatibility_level = 3.6
command_directory = /usr/sbin
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
queue_directory = /var/spool/postfix
mail_owner = postfix

# Network settings
inet_protocols = ipv4
inet_interfaces = all

# SMTP Settings
smtpd_banner = $myhostname ESMTP
smtpd_tls_security_level = none

# Authentication
smtpd_sasl_auth_enable = yes
smtpd_sasl_type = cyrus
smtpd_sasl_path = smtpd
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $mydomain
broken_sasl_auth_clients = yes

# Access restrictions
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination

# Resource limits
message_size_limit = 52428800
mailbox_size_limit = 0

# Logging
maillog_file = /var/log/postfix/postfix.log
debug_peer_level = 2