I am trying to figure what is the problem with my mail server on Google Cloud Platform.
The problem is that none of the user can send mail out of the box, but they can send/receive email each other in spite of being on different domain on the same server, also, mail go outside the box into internet.
Some background: I had a VM setup on Google Cloud Platform, box running CentoOS7, The box comes with one dedicated IP and one internal IP. "CentOS web panel" is been use to manage couple of different website. All things relating to website work perfectly except for mail delivery outside the box.
I make use of the tutorial available on this link to integrate sendgrid on the said instance.
Because, GPC does not allow VM to use port 25 for sending email, I subscribe to one of email provider on GCP, sendgrid and I was provide with its SMTP URL that can use any port aside the block port of VM
Currently below is the content of my postfix main.cf
# Postfix master process configuration file. For details on the format
# of the file, see the Postfix master(5) manual page.
#
# ***** Unused items removed *****
# ==========================================================================
# service type private unpriv chroot wakeup maxproc command + args
# (yes) (yes) (yes) (never) (100)
# ==========================================================================
smtp inet n - n - - smtpd
587 inet n - - - - smtpd
2525 inet n - - - - smtpd
# -o content_filter=smtp-amavis:127.0.0.1:10024
# -o receive_override_options=no_address_mappings
#
## Enable SMTP on port 587 only for authenticated/TLS clients
submission inet n - n - - smtpd
-o smtpd_enforce_tls=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_mynetworks,permit_sasl_authenticated,reject
-o smtpd_recipient_restrictions=permit_mynetworks, permit_sasl_authenticated,reject
#
## Enable SMTP on port 465 only for authenticated/SSL clients
smtps inet n - n - - smtpd
-o smtpd_tls_wrappermode=yes
-o smtpd_sasl_auth_enable=yes
-o smtpd_client_restrictions=permit_mynetworks,permit_sasl_authenticated,reject
#
pickup fifo n - n 60 1 pickup
-o content_filter=
-o receive_override_options=no_header_body_checks
cleanup unix n - n - 0 cleanup
qmgr fifo n - n 300 1 qmgr
#qmgr fifo n - n 300 1 oqmgr
tlsmgr unix - - n 1000? 1 tlsmgr
rewrite unix - - n - - trivial-rewrite
bounce unix - - n - 0 bounce
defer unix - - n - 0 bounce
trace unix - - n - 0 bounce
verify unix - - n - 1 verify
flush unix n - n 1000? 0 flush
proxymap unix - - n - - proxymap
smtp unix - - n - - smtp
# When relaying mail as backup MX, disable fallback_relay to avoid MX loops
relay unix - - n - - smtp
-o fallback_relay=
# -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq unix n - n - - showq
error unix - - n - - error
discard unix - - n - - discard
local unix - n n - - local
virtual unix - n n - - virtual
lmtp unix - - n - - lmtp
anvil unix - - n - 1 anvil
scache unix - - n - 1 scache
#
# ====================================================================
# Interfaces to non-Postfix software. Be sure to examine the manual
# pages of the non-Postfix software to find out what options it wants.
# pages of the non-Postfix software to find out what options it wants.
# ====================================================================
maildrop unix - n n - - pipe
flags=DRhu user=vmail argv=/usr/local/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=foo argv=/usr/local/sbin/bsmtp -f $sender $nexthop $recipient
#
# spam/virus section
#
smtp-amavis unix - - y - 2 smtp
-o smtp_data_done_timeout=1200
-o disable_dns_lookups=yes
-o smtp_send_xforward_command=yes
127.0.0.1:10025 inet n - y - - smtpd
-o content_filter=
-o smtpd_helo_restrictions=
-o smtpd_sender_restrictions=
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o mynetworks=127.0.0.0/8
-o smtpd_error_sleep_time=0
-o smtpd_soft_error_limit=1001
-o smtpd_soft_error_limit=1001
-o smtpd_hard_error_limit=1000
-o receive_override_options=no_header_body_checks
-o smtpd_helo_required=no
-o smtpd_client_restrictions=
-o smtpd_restriction_classes=
-o disable_vrfy_command=no
-o strict_rfc821_envelopes=yes
#
# Dovecot LDA
dovecot unix - n n - - pipe
flags=DRhu user=vmail:mail argv=/usr/libexec/dovecot/deliver -d ${recipient}
#
# SPF check
spfpolicy unix - n n - - spawn
user=nobody argv=/usr/bin/python /usr/libexec/postfix/policyd-spf
and below is my main.cf is as below
# uncomment for debugging if needed
#soft_bounce=yes
# postfix main
mail_owner = postfix
setgid_group = postdrop
delay_warning_time = 4
# postfix paths
html_directory = no
command_directory = /usr/sbin
daemon_directory = /usr/libexec/postfix
queue_directory = /var/spool/postfix
sendmail_path = /usr/sbin/sendmail.postfix
newaliases_path = /usr/bin/newaliases.postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
# network settings
inet_interfaces = all
inet_protocols = ipv4
mydomain = domain.com
myhostname = srv1.domain.com
mynetworks = 127.0.0.0/8 [::1]/128 30.0.0.0/32
mydestination = $mydomain, localhost.$mydomain, localhost
relay_domains = proxy:mysql:/etc/postfix/mysql-relay_domains_maps.cf
# mail delivery
recipient_delimiter = +
# mappings
alias_maps = hash:/etc/aliases
transport_maps = hash:/etc/postfix/transport
#local_recipient_maps =
# virtual setup
virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_alias_default_maps.cf, proxy:mysql:/etc/postfix/mysq$
virtual_mailbox_base = /var/vmail
virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains_maps.cf
virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailbox_maps.cf, proxy:mysql:/etc/postfix/mysql-vi$
virtual_minimum_uid = 101
virtual_uid_maps = static:101
virtual_gid_maps = static:12
virtual_transport = dovecot
dovecot_destination_recipient_limit = 1
# debugging
debug_peer_level = 3
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
xxgdb $daemon_directory/$process_name $process_id & sleep 5
# authentication
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain = $mydomain, srv1.domain.com
broken_sasl_auth_clients = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_recipient_restrictions =permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_sender_restrictions = reject_unknown_sender_domain
# tls config
smtp_use_tls = yes
smtpd_use_tls = yes
smtpd_tls_security_level = may
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
tls_random_source = dev:/dev/urandom
smtp_tls_session_cache_database = btree:$data_directory/smtp_tls_session_cache
# Change mail.example.com.* to your host name
smtpd_tls_key_file = /etc/pki/tls/private/hostname.key
smtpd_tls_cert_file = /etc/pki/tls/certs/hostname.bundle
# rules restrictions
smtpd_helo_restrictions =
smtpd_sender_restrictions =
# uncomment for realtime black list checks
# ,reject_rbl_client zen.spamhaus.org
# ,reject_rbl_client bl.spamcop.net
# ,reject_rbl_client dnsbl.sorbs.net
smtpd_helo_required = yes
unknown_local_recipient_reject_code = 550
disable_vrfy_command = yes
smtpd_data_restrictions = reject_unauth_pipelining
# Other options
message_size_limit = 204800000
mailbox_size_limit = 2048000000
# Vacation Scripts
vacation_destination_recipient_limit = 1
recipient_bcc_maps = proxy:mysql:/etc/postfix/mysql-virtual_vacation.cf
# smtpd_milters setting
milter_mail_macros = i {mail_addr} {client_addr} {client_name} {auth_authen} {auth_type}
smtpd_milters = inet:127.0.0.1:8891
non_smtpd_milters = $smtpd_milters
milter_default_action = accept
milter_protocol = 6
# specify SMTP relay host
default_transport = error
relay_transport = error
relayhost = [smtp.sendgrid.net]:2525
smtp_tls_security_level = encrypt
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
header_size_limit = 4096000
smtp_sasl_security_options = noanonymous
smtp_sasl_mechanism_filter = login
smtpd_banner = $myhostname
and the content of >postconf -n is as below:
alias_maps = hash:/etc/aliases
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
debug_peer_level = 3
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin xxgdb $daemon_directory/$process_name $proces s_id & sleep 5
default_transport = error
delay_warning_time = 4
disable_vrfy_command = yes
dovecot_destination_recipient_limit = 1
header_size_limit = 4096000
html_directory = no
inet_interfaces = all
inet_protocols = ipv4
mail_owner = postfix
mailbox_size_limit = 2048000000
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
message_size_limit = 204800000
milter_default_action = accept
milter_mail_macros = i {mail_addr} {client_addr} {client_name} {auth_authen} {auth_type}
milter_protocol = 6
mydestination = $mydomain, localhost.$mydomain, localhost
mydomain = domain.com
myhostname = srv1.domain.com
mynetworks = 127.0.0.0/8 [::1]/128 30.0.0.0/32
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases.postfix
non_smtpd_milters = $smtpd_milters
queue_directory = /var/spool/postfix
recipient_bcc_maps = proxy:mysql:/etc/postfix/mysql-virtual_vacation.cf
recipient_delimiter = +
relay_domains = proxy:mysql:/etc/postfix/mysql-relay_domains_maps.cf
relay_transport = error
relayhost = [smtp.sendgrid.net]:2525
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_sasl_auth_enable = yes
smtp_sasl_mechanism_filter = login
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_security_level = encrypt
smtp_tls_session_cache_database = btree:$data_directory/smtp_tls_session_cache
smtp_use_tls = yes
smtpd_banner = $myhostname
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_helo_required = yes
smtpd_helo_restrictions =
smtpd_milters = inet:127.0.0.1:8891
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $mydomain, srv1.domain.com
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_restrictions =
smtpd_tls_cert_file = /etc/pki/tls/certs/hostname.bundle
smtpd_tls_key_file = /etc/pki/tls/private/hostname.key
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_security_level = may
smtpd_tls_session_cache_timeout = 3600s
smtpd_use_tls = yes
tls_random_source = dev:/dev/urandom
transport_maps = hash:/etc/postfix/transport
unknown_local_recipient_reject_code = 550
vacation_destination_recipient_limit = 1
virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_alias_default_maps.cf, proxy:mysql:/etc/postfix/mysql-virtual_alias_maps.cf, regexp:/etc/postfix/virtual_regexp
virtual_gid_maps = static:12
virtual_mailbox_base = /var/vmail
virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains_maps.cf
virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailbox_maps.cf, proxy:mysql:/etc/postfix/mysql-virtual_alias_pipe_maps.cf
virtual_minimum_uid = 101
virtual_transport = dovecot
virtual_uid_maps = static:101
Whenever I attempt to send mail outside the server to either gmail/yahoo other from round cube, I got the following error in roundcube interface,
SMTP Error (550): Failed to add recipient "user@gmail.com" (5.1.1 <user@gmail.com>: Recipient address rejected: [smtp.sendgrid.net]:2525).
and in the maillog tail -f /var/log/maillog
I got this section of error:
host postfix/smtpd[31362]: NOQUEUE: reject: RCPT from localhost[127.0.0.1]: 550 5.1.1 <user@gmail.com>: Recipient address rejected: [smtp.sendgrid.net]:2525; from=<info@domain.com> to=<user@gmail.com> proto=ESMTP helo=<localhost>
