LinuxQuestions.org - Postfix can't receive mail

I'm using redhat 8.0 and postfix for mail server. But i can't receive
the mail from the server. I have installed imap-2001a-15.
I don't know why this happen.
Can anyone solve it ?
THX
The posfix main.cf file is shown below:

# Global Postfix configuration file. This file lists only a subset
# of all 100+ parameters. See the sample-xxx.cf files for a full list.
#
# The general format is lines with parameter = value pairs. Lines
# that begin with whitespace continue the previous line. A value can
# contain references to other $names or ${name}s.
#
# NOTE - CHANGE NO MORE THAN 2-3 PARAMETERS AT A TIME, AND TEST IF
# POSTFIX STILL WORKS AFTER EVERY CHANGE.

# SOFT BOUNCE
#
# The soft_bounce parameter provides a limited safety net for
# testing. When soft_bounce is enabled, mail will remain queued that
# would otherwise bounce. This parameter disables locally-generated
# bounces, and prevents the SMTP server from rejecting mail permanently
# (by changing 5xx replies into 4xx replies). However, soft_bounce
# is no cure for address rewriting mistakes or mail routing mistakes.
#
#soft_bounce = no

# LOCAL PATHNAME INFORMATION
#
# The queue_directory specifies the location of the Postfix queue.
# This is also the root directory of Postfix daemons that run chrooted.
# See the files in examples/chroot-setup for setting up Postfix chroot
# environments on different UNIX systems.
#
queue_directory = /var/spool/postfix

# The command_directory parameter specifies the location of all
# postXXX commands. The default value is $program_directory.
#
command_directory = /usr/sbin

# The daemon_directory parameter specifies the location of all Postfix
# daemon programs (i.e. programs listed in the master.cf file). The
# default value is $program_directory. This directory must be owned
# by root.
#
daemon_directory = /usr/libexec/postfix

# QUEUE AND PROCESS OWNERSHIP
#
# The mail_owner parameter specifies the owner of the Postfix queue
# and of most Postfix daemon processes. Specify the name of a user
# account THAT DOES NOT SHARE ITS USER OR GROUP ID WITH OTHER ACCOUNTS
# AND THAT OWNS NO OTHER FILES OR PROCESSES ON THE SYSTEM. In
# particular, don't specify nobody or daemon. PLEASE USE A DEDICATED
# USER.
#
mail_owner = postfix

# The default_privs parameter specifies the default rights used by
# the local delivery agent for delivery to external file or command.
# These rights are used in the absence of a recipient user context.
# DO NOT SPECIFY A PRIVILEGED USER OR THE POSTFIX OWNER.
#
#default_privs = nobody

# INTERNET HOST AND DOMAIN NAMES
#
# The myhostname parameter specifies the internet hostname of this
# mail system. The default is to use the fully-qualified domain name
# from gethostname(). $myhostname is used as a default value for many
# other configuration parameters.
#
#myhostname = host.domain.tld
myhostname = yung.no-ip.biz

# The mydomain parameter specifies the local internet domain name.
# The default is to use $myhostname minus the first component.
# $mydomain is used as a default value for many other configuration
# parameters.
#
mydomain = no-ip.biz

# SENDING MAIL
#
# The myorigin parameter specifies the domain that locally-posted
# mail appears to come from. The default is to append $myhostname,
# which is fine for small sites. If you run a domain with multiple
# machines, you should (1) change this to $mydomain and (2) set up
# a domain-wide alias database that aliases each user to
# user@that.users.mailhost.
#
myorigin = $myhostname
#myorigin = $mydomain

# RECEIVING MAIL

# The inet_interfaces parameter specifies the network interface
# addresses that this mail system receives mail on. By default,
# the software claims all active interfaces on the machine. The
# parameter also controls delivery of mail to user@[ip.address].
#
#inet_interfaces = localhost
inet_interfaces = all
#inet_interfaces = $myhostname
#inet_interfaces = $myhostname, localhost

# The mydestination parameter specifies the list of domains that this
# machine considers itself the final destination for. That includes
# Sendmail-style virtual domains hosted on this machine.
#
# Do not include Postfix-style virtual domains - those domains are
# specified elsewhere (see sample-virtual.cf, and sample-transport.cf).
#
# The default is $myhostname + localhost.$mydomain. On a mail domain
# gateway, you should also include $mydomain. Do not specify the
# names of domains that this machine is backup MX host for. Specify
# those names via the relay_domains or permit_mx_backup settings for
# the SMTP server (see sample-smtpd.cf).
#
# The local machine is always the final destination for mail addressed
# to user@[the.net.work.address] of an interface that the mail system
# receives mail on (see the inet_interfaces parameter).
#
# Specify a list of host or domain names, /file/name or type:table
# patterns, separated by commas and/or whitespace. A /file/name
# pattern is replaced by its contents; a type:table is matched when
# a name matches a lookup key. Continue long lines by starting the
# next line with whitespace.
#
mydestination = yung.no-ip.biz
#mydestination = $myhostname, localhost.$mydomain $mydomain
#mydestination = $myhostname, localhost.$mydomain, $mydomain,
# mail.$mydomain, www.$mydomain, ftp.$mydomain

# TRUST AND RELAY CONTROL

# The mynetworks parameter specifies the list of "trusted" SMTP
# clients that have more privileges than "strangers".
#
# In particular, "trusted" SMTP clients are allowed to relay mail
# through Postfix. See the smtpd_recipient_restrictions parameter
# in file sample-smtpd.cf.
#
# You can specify the list of "trusted" network addresses by hand
# or you can let Postfix do it for you (which is the default).
#
# By default (mynetworks_style = subnet), Postfix "trusts" SMTP
# clients in the same IP subnetworks as the local machine.
# On Linux, this does works correctly only with interfaces specified
# with the "ifconfig" command.
#
# Specify "mynetworks_style = class" when Postfix should "trust" SMTP
# clients in the same IP class A/B/C networks as the local machine.
# Don't do this with a dialup site - it would cause Postfix to "trust"
# your entire provider's network. Instead, specify an explicit
# mynetworks list by hand, as described below.
#
# Specify "mynetworks_style = host" when Postfix should "trust"
# only the local machine.
#
#mynetworks_style = class
#mynetworks_style = subnet
#mynetworks_style = host

# Alternatively, you can specify the mynetworks list by hand, in
# which case Postfix ignores the mynetworks_style setting.
#
# Specify an explicit list of network/netmask patterns, where the
# mask specifies the number of bits in the network part of a host
# address.
#
# You can also specify the absolute pathname of a pattern file instead
# of listing the patterns here. Specify type:table for table-based lookups
# (the value on the table right-hand side is not used).
#
mynetworks = 192.168.1.0/24
#mynetworks = $config_directory/mynetworks
#mynetworks = hash:/etc/postfix/network_table

# The relay_domains parameter restricts what clients this mail system
# will relay mail from, or what destinations this system will relay
# mail to. See the smtpd_recipient_restrictions restriction in the
# file sample-smtpd.cf for detailed information.
#
# By default, Postfix relays mail
# - from "trusted" clients whose IP address matches $mynetworks,
# - from "trusted" clients matching $relay_domains or subdomains thereof,
# - from untrusted clients to destinations that match $relay_domains
# or subdomains thereof, except addresses with sender-specified routing.
# The default relay_domains value is $mydestination.
#
# In addition to the above, the Postfix SMTP server by default accepts mail
# that Postfix is final destination for:
# - destinations that match $inet_interfaces,
# - destinations that match $mydestination
# - destinations that match $virtual_maps.
# These destinations do not need to be listed in $relay_domains.
#
# Specify a list of hosts or domains, /file/name patterns or type:name
# lookup tables, separated by commas and/or whitespace. Continue
# long lines by starting the next line with whitespace. A file name
# is replaced by its contents; a type:name table is matched when a
# (parent) domain appears as lookup key.
#
# NOTE: Postfix will not automatically forward mail for domains that
# list this system as their primary or backup MX host. See the
# permit_mx_backup restriction in the file sample-smtpd.cf.
#
relay_domains = yung.no-ip.biz

# INTERNET OR INTRANET

# The relayhost parameter specifies the default host to send mail to
# when no entry is matched in the optional transport(5) table. When
# no relayhost is given, mail is routed directly to the destination.
#
# On an intranet, specify the organizational domain name. If your
# internal DNS uses no MX records, specify the name of the intranet
# gateway host instead.
#
# In the case of SMTP, specify a domain, host, host:port, [host]:port,
# [address] or [address]:port; the form [host] turns off MX lookups.
#
# If you're connected via UUCP, see also the default_transport parameter.
#
#relayhost = $mydomain
#relayhost = gateway.my.domain
#relayhost = uucphost
#relayhost = [an.ip.add.ress]
relayhost = mail.netvigator.com

# REJECTING UNKNOWN LOCAL USERS
#
# The local_recipient_maps parameter specifies optional lookup tables
# with all names (not addresses) of users that are local with respect
# to $mydestination and $inet_interfaces. If this parameter is
# defined, then the SMTP server will reject mail for unknown local
# users.
#
# If you use the default Postfix local delivery agent for local
# delivery, uncomment the definition below.
#
# Beware: if the Postfix SMTP server runs chrooted, you may have to
# copy the passwd (not shadow) database into the jail. This is
# system dependent.
#
#local_recipient_maps = $alias_maps unix:passwd.byname

# INPUT RATE CONTROL
#
# The in_flow_delay configuration parameter implements mail input
# flow control. This feature is turned on by default, although it
# still needs further development (it's disabled on SCO UNIX due
# to an SCO bug).
#
# A Postfix process will pause for $in_flow_delay seconds before
# accepting a new message, when the message arrival rate exceeds the
# message delivery rate. With the default 50 SMTP server process
# limit, this limits the mail inflow to 50 messages a second more
# than the number of messages delivered per second.
#
# Specify 0 to disable the feature. Valid delays are 0..10.
#
#in_flow_delay = 1s

# ADDRESS REWRITING
#
# Insert text from sample-rewrite.cf if you need to do address
# masquerading.
#
# Insert text from sample-canonical.cf if you need to do address
# rewriting, or if you need username->Firstname.Lastname mapping.

# ADDRESS REDIRECTION (VIRTUAL DOMAIN)
#
# Insert text from sample-virtual.cf if you need virtual domain support.

# "USER HAS MOVED" BOUNCE MESSAGES
#
# Insert text from sample-relocated.cf if you need "user has moved"
# style bounce messages. Alternatively, you can bounce recipients
# with an SMTP server access table. See sample-smtpd.cf.

# TRANSPORT MAP
#
# Insert text from sample-transport.cf if you need explicit routing.

# ALIAS DATABASE
#
# The alias_maps parameter specifies the list of alias databases used
# by the local delivery agent. The default list is system dependent.
# On systems with NIS, the default is to search the local alias
# database, then the NIS alias database. See aliases(5) for syntax
# details.
#
# If you change the alias database, run "postalias /etc/aliases" (or
# wherever your system stores the mail alias file), or simply run
# "newaliases" to build the necessary DBM or DB file.
#
# It will take a minute or so before changes become visible. Use
# "postfix reload" to eliminate the delay.
#
#alias_maps = dbm:/etc/aliases
alias_maps = hash:/etc/postfix/aliases
#alias_maps = hash:/etc/aliases, nis:mail.aliases
#alias_maps = netinfo:/aliases

# The alias_database parameter specifies the alias database(s) that
# are built with "newaliases" or "sendmail -bi". This is a separate
# configuration parameter, because alias_maps (see above) may specify
# tables that are not necessarily all under control by Postfix.
#
#alias_database = dbm:/etc/aliases
#alias_database = dbm:/etc/mail/aliases
#alias_database = hash:/etc/aliases
#alias_database = hash:/etc/aliases, hash:/opt/majordomo/aliases

# ADDRESS EXTENSIONS (e.g., user+foo)
#
# The recipient_delimiter parameter specifies the separator between
# user names and address extensions (user+foo). See canonical(5),
# local(8), relocated(5) and virtual(5) for the effects this has on
# aliases, canonical, virtual, relocated and .forward file lookups.
# Basically, the software tries user+foo and .forward+foo before
# trying user and .forward.
#
#recipient_delimiter = +

# DELIVERY TO MAILBOX
#
# The home_mailbox parameter specifies the optional pathname of a
# mailbox file relative to a user's home directory. The default
# mailbox file is /var/spool/mail/user or /var/mail/user. Specify
# "Maildir/" for qmail-style delivery (the / is required).
#
#home_mailbox = Mailbox
#home_mailbox = Maildir/

# The mail_spool_directory parameter specifies the directory where
# UNIX-style mailboxes are kept. The default setting depends on the
# system type.
#
#mail_spool_directory = /var/mail
#mail_spool_directory = /var/spool/mail

# The mailbox_command parameter specifies the optional external
# command to use instead of mailbox delivery. The command is run as
# the recipient with proper HOME, SHELL and LOGNAME environment settings.
# Exception: delivery for root is done as $default_user.
#
# Other environment variables of interest: USER (recipient username),
# EXTENSION (address extension), DOMAIN (domain part of address),
# and LOCAL (the address localpart).
#
# Unlike other Postfix configuration parameters, the mailbox_command
# parameter is not subjected to $parameter substitutions. This is to
# make it easier to specify shell syntax (see example below).
#
# Avoid shell meta characters because they will force Postfix to run
# an expensive shell process. Procmail alone is expensive enough.
#
# IF YOU USE THIS TO DELIVER MAIL SYSTEM-WIDE, YOU MUST SET UP AN
# ALIAS THAT FORWARDS MAIL FOR ROOT TO A REAL USER.
#
#mailbox_command = /some/where/procmail
#mailbox_command = /some/where/procmail -a "$EXTENSION"

# The mailbox_transport specifies the optional transport in master.cf
# to use after processing aliases and .forward files. This parameter
# has precedence over the mailbox_command, fallback_transport and
# luser_relay parameters.
#
# Specify a string of the form transport:nexthop, where transport is
# the name of a mail delivery transport defined in master.cf. The
# :nexthop part is optional. For more details see the sample transport
# configuration file.
#
#mailbox_transport = lmtp:unix:/file/name
#mailbox_transport = cyrus

# The fallback_transport specifies the optional transport in master.cf
# to use for recipients that are not found in the UNIX passwd database.
# This parameter has precedence over the luser_relay parameter.
#
# Specify a string of the form transport:nexthop, where transport is
# the name of a mail delivery transport defined in master.cf. The
# :nexthop part is optional. For more details see the sample transport
# configuration file.
#
#fallback_transport = lmtp:unix:/file/name
#fallback_transport = cyrus
#fallback_transport =

# The luser_relay parameter specifies an optional destination address
# for unknown recipients. By default, mail for unknown local recipients
# is bounced.
#
# The following expansions are done on luser_relay: $user (recipient
# username), $shell (recipient shell), $home (recipient home directory),
# $recipient (full recipient address), $extension (recipient address
# extension), $domain (recipient domain), $local (entire recipient
# localpart), $recipient_delimiter. Specify ${name?value} or
# ${name:value} to expand value only when $name does (does not) exist.
#
# luser_relay works only for the default Postfix local delivery agent.
#
#luser_relay = $user@other.host
#luser_relay = $local@other.host
#luser_relay = admin+$local

# JUNK MAIL CONTROLS
#
# The controls listed here are only a very small subset. See the file
# sample-smtpd.cf for an elaborate list of anti-UCE controls.

# The header_checks parameter specifies an optional table with patterns
# that each logical message header is matched against, including
# headers that span multiple physical lines. Patterns are matched
# in the specified order, and the search stops upon the first match.
# When a pattern matches, what happens next depends on the associated
# action that is specified in the right-hand side of the table:
#
# REJECT the entire message is rejected.
# REJECT text.... The text is sent to the originator.
# IGNORE the header line is silently discarded.
# WARN the header is logged (not rejected) with a warning message.
# WARN text... as above, and the text is logged, too.
#
# These patterns do not apply to MIME headers in the message body.
#
# See also the body_checks example in the sample-filter.cf file.
#
#header_checks = regexp:/etc/postfix/header_checks

# FAST ETRN SERVICE
#
# Postfix maintains per-destination logfiles with information about
# deferred mail, so that mail can be flushed quickly with the SMTP
# "ETRN domain.tld" command, or by executing "sendmail -qRdomain.tld".
#
# By default, Postfix maintains deferred mail logfile information
# only for destinations that Postfix is willing to relay to (as
# specified in the relay_domains parameter). For other destinations,
# Postfix attempts to deliver ALL queued mail after receiving the
# SMTP "ETRN domain.tld" command, or after execution of "sendmail
# -qRdomain.tld". This can be slow when a lot of mail is queued.
#
# The fast_flush_domains parameter controls what destinations are
# eligible for this "fast ETRN/sendmail -qR" service.
#
#fast_flush_domains = $relay_domains
#fast_flush_domains =

# SHOW SOFTWARE VERSION OR NOT
#
# The smtpd_banner parameter specifies the text that follows the 220
# code in the SMTP server's greeting banner. Some people like to see
# the mail version advertised. By default, Postfix shows no version.
#
# You MUST specify $myhostname at the start of the text. That is an
# RFC requirement. Postfix itself does not care.
#
#smtpd_banner = $myhostname ESMTP $mail_name
#smtpd_banner = $myhostname ESMTP $mail_name ($mail_version)

# PARALLEL DELIVERY TO THE SAME DESTINATION
#
# How many parallel deliveries to the same user or domain? With local
# delivery, it does not make sense to do massively parallel delivery
# to the same user, because mailbox updates must happen sequentially,
# and expensive pipelines in .forward files can cause disasters when
# too many are run at the same time. With SMTP deliveries, 10
# simultaneous connections to the same domain could be sufficient to
# raise eyebrows.
#
# Each message delivery transport has its XXX_destination_concurrency_limit
# parameter. The default is $default_destination_concurrency_limit for
# most delivery transports. For the local delivery agent the default is 2.

#local_destination_concurrency_limit = 2
#default_destination_concurrency_limit = 10

# DEBUGGING CONTROL
#
# The debug_peer_level parameter specifies the increment in verbose
# logging level when an SMTP client or server host name or address
# matches a pattern in the debug_peer_list parameter.
#
debug_peer_level = 2

# The debug_peer_list parameter specifies an optional list of domain
# or network patterns, /file/name patterns or type:name tables. When
# an SMTP client or server host name or address matches a pattern,
# increase the verbose logging level by the amount specified in the
# debug_peer_level parameter.
#
#debug_peer_list = 127.0.0.1
#debug_peer_list = some.domain

# The debugger_command specifies the external command that is executed
# when a Postfix daemon program is run with the -D option.
#
# Use "command .. & sleep 5" so that the debugger can attach before
# the process marches on. If you use an X-based debugger, be sure to
# set up your XAUTHORITY environment variable before starting Postfix.
#
debugger_command =
PATH=/usr/bin:/usr/X11R6/bin
xxgdb $daemon_directory/$process_name $process_id & sleep 5

# INSTALL-TIME CONFIGURATION INFORMATION
#
# The following parameters are used when installing a new Postfix version.
#
# sendmail_path: The full pathname of the Postfix sendmail command.
# This is the Sendmail-compatible mail posting interface.
#
sendmail_path = /usr/sbin/sendmail.postfix

# newaliases_path: The full pathname of the Postfix newaliases command.
# This is the Sendmail-compatible command to build alias databases.
#
newaliases_path = /usr/bin/newaliases.postfix

# mailq_path: The full pathname of the Postfix mailq command. This
# is the Sendmail-compatible mail queue listing command.
#
mailq_path = /usr/bin/mailq.postfix

# setgid_group: The group for mail submission and queue management
# commands. This must be a group name with a numerical group ID that
# is not shared with other accounts, not even with the Postfix account.
#
setgid_group = postdrop

# manpage_directory: The location of the Postfix on-line manual pages.
#
manpage_directory = /usr/share/man

# sample_directory: The location of the Postfix sample configuration files.
#
sample_directory = /usr/share/doc/postfix-1.1.11/samples

# readme_directory: The location of the Postfix README files.
#
readme_directory = /usr/share/doc/postfix-1.1.11/README_FILES
alias_database = hash:/etc/postfix/aliases