Postfix send email but not receive it. NOQUEUE: reject: RCPT from ; Relay access denied

Question

Postfix was configured and it can send emails using gmail domain relay. However Postfix can't receive emails from external domains.

My internal email is: [email protected]

Versions: Ubuntu 17.10 (Artful Aardvark) ; Postfix 3.2.3

Below my setups;

• The ports 25 and 587 are open in GCP where postfix was configured

• There is an user commercial name created in Linux where postfix was configured

• MX and A DNS were setup and below you can see report yielded from dig linux command:

Below my extra setups;

something.com.         59      IN      MX      10 mail.something.com.
mail.something.com.    59      IN      A       <SOMETHING IP ADDRESS>

$ sudo postconf -n

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
append_dot_mydomain = no
biff = no
compatibility_level = 2
home_mailbox = Maildir/
inet_interfaces = all
inet_protocols = all
mailbox_size_limit = 0
mydestination = $myhostname mail.$myhostname localhost.$mydomain localhost
myhostname = something.com
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
myorigin = /etc/mailname
readme_directory = no
recipient_delimiter = +
relayhost = [smtp.gmail.com]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options =
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtp_use_tls = yes
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

$ sudo postconf -M

smtp       inet  n       -       y       -       -       smtpd
submission inet  n       -       y       -       -       smtpd
pickup     unix  n       -       y       60      1       pickup
cleanup    unix  n       -       y       -       0       cleanup
qmgr       unix  n       -       n       300     1       qmgr
tlsmgr     unix  -       -       y       1000?   1       tlsmgr
rewrite    unix  -       -       y       -       -       trivial-rewrite
bounce     unix  -       -       y       -       0       bounce
defer      unix  -       -       y       -       0       bounce
trace      unix  -       -       y       -       0       bounce
verify     unix  -       -       y       -       1       verify
flush      unix  n       -       y       1000?   0       flush
proxymap   unix  -       -       n       -       -       proxymap
proxywrite unix  -       -       n       -       1       proxymap
smtp       unix  -       -       y       -       -       smtp
relay      unix  -       -       y       -       -       smtp
showq      unix  n       -       y       -       -       showq
error      unix  -       -       y       -       -       error
retry      unix  -       -       y       -       -       error
discard    unix  -       -       y       -       -       discard
local      unix  -       n       n       -       -       local
virtual    unix  -       n       n       -       -       virtual
lmtp       unix  -       -       y       -       -       lmtp
anvil      unix  -       -       y       -       1       anvil
scache     unix  -       -       y       -       1       scache
maildrop   unix  -       n       n       -       -       pipe flags=DRhu user=vmail argv=/usr/bin/maildrop -d ${recipient}
uucp       unix  -       n       n       -       -       pipe flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
ifmail     unix  -       n       n       -       -       pipe flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp      unix  -       n       n       -       -       pipe flags=Fq. user=bsmtp argv=/usr/lib/bsmtp/bsmtp -t$nexthop -f$sender $recipient
scalemail-backend unix - n       n       -       2       pipe flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store ${nexthop} ${user} ${extension}
mailman    unix  -       n       n       -       -       pipe flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py ${nexthop} ${user}

I spent a lot of hours trying to solve it but until now I couldn't because probably it's not my main skill. I'm getting better...

Could you please check it and guide me to turn on the postfix to receive email? Thanks

Solution

Your mydestination doesn't have mail.example.com, just the plain example.com.

mydestination = $myhostname localhost.$mydomain localhost
myhostname = example.com

You could add it e.g. like this:

mydestination = $myhostname mail.$myhostname localhost.$mydomain localhost

However, you probably want to receive mail for [email protected], not mail.example.com? For this you'd need to set MX for it, instead:

example.com.         IN      MX      10 mail.example.com.
mail.example.com.    IN      A       198.51.100.100

Comments

[Marcos]

I did what you told me. Postfix sends email, but to receive the message: "NOQUEUE: reject" "Relay access denied" still continue showing on the log file. I mean, postfix doesn't receive email from external domains.

[Marcos]

checking deeply the configuration I solve it. Thanks to Esa Jokinen for your insights. The setups are updated to help some friend on it.

[Esa Jokinen]

Due to the Q/A nature it'd be better if you keep the errors on your question and answer with the necessary modifications.

[kittygirl]

@EsaJokinen, DNS setting should use @ instead of domain.com.For example,@ IN MX 10 mail.example.com.

[Esa Jokinen]

@kittygirl: The @ is substituted with zone apex in the BIND zones. Therefore, @ equals example.com. and both can be used, but @ alone in examples doesn't mean anything specific. See zytrax.com/books/dns/apa/origin.html

[kittygirl]

@EsaJokinen,with your DNS setting, only change myhostname = example.com to myhostname = mail.example.com.is that ok?

[Esa Jokinen]

That would require additional example.com in mydestination.