postfix is unable to send email

[boson code]

Whenever i try to send an email from my server, i get the following error:

Nov 13 06:37:21 xyz postfix/smtpd[6730]:connect from unknown[a.b.c.d]

Nov 13 06:37:21 xyz postfix/smtp[6729]: warning: host X.com[x.y.z.d]:25 greeted me with my own hostname xyz.biz

Nov 13 06:37:21 xyz postfix/smtp[6729]: warning: host X.com[x.y.z.d]:25 replied to HELO/EHLO with my own hostname xyz.biz

Nov 13 06:37:21 xyz postfix/smtp[6729]: 2017F1B00C54: to=<du...@X.com>, relay=X.com[x.y.z.d]:25, delay=0.98, delays=0.17/0/0.81/0, dsn=5.4.6, status=bounced (mail for X.com loops back to myself)

this is the output of postconf -n:

address_verify_poll_delay = 1s
alias_database = hash:/etc/aliases
alias_maps =
body_checks_size_limit = 40980000
command_directory = /usr/sbin
config_directory = /etc/postfix
connection_cache_ttl_limit = 300000s
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 1
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5
default_delivery_slot_cost = 2
default_destination_concurrency_limit = 10
default_destination_recipient_limit = 1
default_minimum_delivery_slots = 3
default_process_limit = 10
default_recipient_refill_delay = 1s
default_recipient_refill_limit = 10
enable_original_recipient = no
hash_queue_depth = 2
home_mailbox = Maildir/
html_directory = no
in_flow_delay = 0
inet_interfaces = all
inet_protocols = ipv4
initial_destination_concurrency = 100
local_header_rewrite_clients =
mail_owner = postfix
mailq_path = /usr/bin/mailq
manpage_directory = /usr/share/man
master_service_disable =
milter_default_action = accept
milter_protocol = 6
mydestination = $myhostname, localhost.localdomain, localhost, $mydomain
mydomain = xyz.biz
myhostname = xyz.biz
mynetworks = 168.100.189.0/28, 127.0.0.0/8
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases
non_smtpd_milters = $smtpd_milters
qmgr_message_active_limit = 500
qmgr_message_recipient_limit = 500
qmgr_message_recipient_minimum = 1
queue_directory = /var/spool/postfix
queue_run_delay = 300s
readme_directory = /usr/share/doc/postfix.20.10.2/README_FILE
receive_override_options = no_header_body_checks
sample_directory = /usr/share/doc/postfix.2.10.2/examples
sendmail_path = /usr/sbin/sendmail
service_throttle_time = 1s
setgid_group = postdrop
smtp_always_send_ehlo = no
smtp_connect_timeout = 1s
smtp_connection_cache_time_limit = 30000s
smtp_connection_reuse_time_limit = 30000s
smtp_delivery_slot_cost = 2
smtp_destination_concurrency_limit = 10000
smtp_destination_rate_delay = 0s
smtp_destination_recipient_limit = 1
smtp_minimum_delivery_slots = 1
smtp_recipient_refill_delay = 1s
smtp_recipient_refill_limit = 1000
smtpd_delay_open_until_valid_rcpt = no
smtpd_delay_reject = no
smtpd_discard_ehlo_keywords = silent-discard, dsn
smtpd_milters = inet:127.0.0.1:8891
smtpd_peername_lookup = no
unknown_local_recipient_reject_code = 550

What could be the reason?

Thank you

[Viktor Dukhovni]

On Wed, Nov 13, 2013 at 08:34:51AM -0800, boson code wrote:

> Whenever I try to send an email from my server, I get the following error:

>
> Nov 13 06:37:21 xyz postfix/smtpd[6730]:connect from unknown[a.b.c.d]
> Nov 13 06:37:21 xyz postfix/smtp[6729]: warning: host X.com[x.y.z.d]:25
> greeted me with my own hostname xyz.biz
> Nov 13 06:37:21 xyz postfix/smtp[6729]: warning: host X.com[x.y.z.d]:25
> replied to HELO/EHLO with my own hostname xyz.biz
> Nov 13 06:37:21 xyz postfix/smtp[6729]: 2017F1B00C54: to=<du...@X.com>,
> relay=X.com[x.y.z.d]:25, delay=0.98, delays=0.17/0/0.81/0, dsn=5.4.6,
> status=bounced (mail for X.com loops back to myself)

Obfuscating the IP addresses and domains makes it very difficult
to help you. The recipient domain was not configured for local
delivery, and yet its best MX host appears to be your system.
See http://www.postfix.org/BASIC_CONFIGURATION_README.html

Below your configuration is almost entirely a misguided mess of
conflicting an unwise settings. Throw it all away and start from
scratch with something small that changes just a few parameters
(mydestination, mynetworks, ...) and leaves the rest at default
values. Make that work, and DO NOT randomly tweak settings you
don't understand.

> address_verify_poll_delay = 1s

This is too aggressive.

> body_checks_size_limit = 40980000
> receive_override_options = no_header_body_checks

While this is a waste of CPU, assuming body checks
actually take place via master.cf overrides...

> connection_cache_ttl_limit = 300000s

> smtp_connection_cache_time_limit = 30000s
> smtp_connection_reuse_time_limit = 30000s

This is inconsiderate ABUSE of remote system resources. Restore
these settings back to default values.

> default_delivery_slot_cost = 2
> default_minimum_delivery_slots = 3

> default_recipient_refill_delay = 1s
> default_recipient_refill_limit = 10

> smtp_delivery_slot_cost = 2

> smtp_minimum_delivery_slots = 1
> smtp_recipient_refill_delay = 1s
> smtp_recipient_refill_limit = 1000

You probably should not be changing these.

> default_destination_concurrency_limit = 10
> default_destination_recipient_limit = 1

This is a terrible idea. Concurrency is now counted per-recipient,
not per-destinatin.

> default_process_limit = 10

> qmgr_message_active_limit = 500
> qmgr_message_recipient_limit = 500
> qmgr_message_recipient_minimum = 1

Are you running on a Raspberry Pi?

> hash_queue_depth = 2

And yet building up very large queues?

> service_throttle_time = 1s

This is crazy, reset back to approximately default value.

> smtp_connect_timeout = 1s

This is way too aggressive for general use. Are you isolated
from the Internet?

> smtp_destination_concurrency_limit = 10000
> smtp_destination_recipient_limit = 1

How on earth is that Raspberry Pi managing 10000 concurrent connections to
each individual recipient?

> smtpd_delay_open_until_valid_rcpt = no
> smtpd_delay_reject = no

Unwise.

--
Viktor.