只有域名能否注册企业邮箱

# 安装Postfix
sudo apt-get update
sudo apt-get install postfix

# 配置Postfix
sudo nano /etc/postfix/main.cf

myhostname = mail.example.com
mydomain = example.com
myorigin = $mydomain
inet_interfaces = all
inet_protocols = ipv4
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
relayhost =
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no
append_dot_mydomain = no
readme_directory = no
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination
smtpd_sender_restrictions = reject_sender_login_mismatch
smtpd_tls_security_level = encrypt
smtp_tls_security_level = encrypt
smtp_use_tls = yes
smtpd_tls_eecdh_grade = strong
smtp_tls_eecdh_grade = strong

sudo systemctl restart postfix