Postfix can send, but not receive external email.

Here is my output for postconf -n:

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
home_mailbox = Maildir/
inet_interfaces = all
inet_protocols = all
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
milter_default_action = accept
milter_protocol = 2
mydestination = $myhostname, mail.mydomain.com, mydomain.com, Mydomain, localhost.localdomain, localhost
myhostname = mail.mydomain.com
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
myorigin = /etc/mailname
readme_directory = no
recipient_delimiter = +
relayhost =
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
virtual_alias_maps = hash:/etc/postfix/virtual

I’m able to send out email to Gmail, etc., without a hitch. But when I try sending an email from my Gmail to my server, it doesn’t work. I don’t get any messages on /var/log/mail.log so I’m not sure what’s going on.

Thanks!