==== Required information ====
- iRedMail version: 0.7.4
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Linux/BSD distribution name and version: CentOS 5.7
- Related log if you're reporting an issue:
====
Hi Zhang,
Please HELP to solve this problem.

We can send Email to Outside World (Gmail, etc.) but can't  send Email from Outside World (Gmail, etc.) to our Mail System. However, some mails are coming to our mail after much delay. Others are lost in transit. Everything was OK before. This started only after we switched to new ISP. I have Googled a lot for past two days... but found no clue.

Email sent from Our Mail to Gmail reached successfully. The header information seems to be OK.
Delivered-To: subhasis.stpl@gmail.com
Received: by 10.114.77.226 with SMTP id v2csp174844ldw;
        Sat, 7 Dec 2013 08:05:13 -0800 (PST)
X-Received: by 10.68.129.201 with SMTP id ny9mr10931127pbb.70.1386432313042;
        Sat, 07 Dec 2013 08:05:13 -0800 (PST)
Return-Path: <subhasis.bhattacharyya@semaphoreindia.com>
Received: from mx.semaphoreindia.com ([27.49.39.194])
        by mx.google.com with ESMTP id w3si1936649pbh.359.2013.12.07.08.05.08
        for <subhasis.stpl@gmail.com>;
        Sat, 07 Dec 2013 08:05:09 -0800 (PST)
Received-SPF: pass (google.com: domain of subhasis.bhattacharyya@semaphoreindia.com designates 27.49.39.194 as permitted sender) client-ip=27.49.39.194;
Authentication-Results: mx.google.com;
       spf=pass (google.com: domain of subhasis.bhattacharyya@semaphoreindia.com designates 27.49.39.194 as permitted sender) smtp.mail=subhasis.bhattacharyya@semaphoreindia.com;
       dkim=pass header.i=@semaphoreindia.com

#vi /var/log/maillog   shows full of STARTTLS errors as below:
....
Dec  8 13:47:59 mx postfix/smtpd[5152]: connect from unknown[210.212.29.188]
Dec  8 13:47:59 mx postfix/smtpd[5152]: warning: network_biopair_interop: error reading 5 bytes from the network: Connection reset by peer
Dec  8 13:47:59 mx postfix/smtpd[5152]: SSL_accept error from unknown[210.212.29.188]: -1
Dec  8 13:47:59 mx postfix/smtpd[5152]: lost connection after STARTTLS from unknown[210.212.29.188]
Dec  8 13:47:59 mx postfix/smtpd[5152]: disconnect from unknown[210.212.29.188]
....
Reason for this is unknown to me.

# postconf -n  => Output given below
alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
allow_min_user = no
biff = no
bounce_queue_lifetime = 1d
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
delay_warning_time = 0h
disable_vrfy_command = yes
enable_original_recipient = no
home_mailbox = Maildir/
html_directory = no
inet_interfaces = all
inet_protocols = ipv4
mail_owner = postfix
mailbox_command = /usr/libexec/dovecot/deliver
mailbox_size_limit = 51200000
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
maximal_backoff_time = 4000s
maximal_queue_lifetime = 1d
message_size_limit = 31457280
minimal_backoff_time = 300s
mydestination = $myhostname, localhost, localhost.localdomain, localhost.$myhostname
mydomain = semaphoreindia.com
myhostname = mx.semaphoreindia.com
mynetworks = 127.0.0.0/8 172.16.10.0/24
mynetworks_style = subnet
myorigin = mx.semaphoreindia.com
newaliases_path = /usr/bin/newaliases.postfix
proxy_interfaces = 27.49.39.194
proxy_read_maps = $canonical_maps $lmtp_generic_maps $local_recipient_maps $mydestination $mynetworks $recipient_bcc_maps $recipient_canonical_maps $relay_domains $relay_recipient_maps $relocated_maps $sender_bcc_maps $sender_canonical_maps $smtp_generic_maps $smtpd_sender_login_maps $transport_maps $virtual_alias_domains $virtual_alias_maps $virtual_mailbox_domains $virtual_mailbox_maps $smtpd_sender_restrictions
queue_directory = /var/spool/postfix
queue_run_delay = 300s
readme_directory = /usr/share/doc/postfix-2.5.9/README_FILES
recipient_bcc_maps = proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_domain.cf, proxy:mysql:/etc/postfix/mysql/recipient_bcc_maps_user.cf
recipient_delimiter = +
relay_domains = $mydestination, proxy:mysql:/etc/postfix/mysql/relay_domains.cf
sample_directory = /usr/share/doc/postfix-2.5.9/samples
sender_bcc_maps = proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_domain.cf, proxy:mysql:/etc/postfix/mysql/sender_bcc_maps_user.cf
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_data_init_timeout = 240s
smtp_data_xfer_timeout = 600s
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_enforce_tls = no
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks,permit_sasl_authenticated, check_helo_access pcre:/etc/postfix/helo_access.pcre
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unlisted_recipient, check_policy_service inet:127.0.0.1:7777, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, check_policy_service inet:127.0.0.1:10031
smtpd_reject_unlisted_recipient = yes
smtpd_reject_unlisted_sender = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = no
smtpd_sasl_local_domain =
smtpd_sasl_path = ./dovecot-auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_login_maps = proxy:mysql:/etc/postfix/mysql/sender_login_maps.cf
smtpd_sender_restrictions = reject_unknown_sender_domain, reject_non_fqdn_sender, permit_mynetworks, reject_sender_login_mismatch, permit_sasl_authenticated
smtpd_tls_CAfile = /etc/pki/tls/certs/iRedMail_CA.pem
smtpd_tls_cert_file = /etc/pki/tls/certs/iRedMail_CA.pem
smtpd_tls_key_file = /etc/pki/tls/private/iRedMail.key
smtpd_tls_loglevel = 0
smtpd_tls_security_level = may
tls_random_source = dev:/dev/urandom
transport_maps = proxy:mysql:/etc/postfix/mysql/transport_maps_user.cf, proxy:mysql:/etc/postfix/mysql/transport_maps_domain.cf
unknown_local_recipient_reject_code = 550
virtual_alias_domains =
virtual_alias_maps = proxy:mysql:/etc/postfix/mysql/virtual_alias_maps.cf, proxy:mysql:/etc/postfix/mysql/domain_alias_maps.cf, proxy:mysql:/etc/postfix/mysql/catchall_maps.cf, proxy:mysql:/etc/postfix/mysql/domain_alias_catchall_maps.cf
virtual_gid_maps = static:500
virtual_mailbox_base = /var/vmail
virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql/virtual_mailbox_domains.cf
virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql/virtual_mailbox_maps.cf
virtual_minimum_uid = 500
virtual_transport = dovecot
virtual_uid_maps = static:500
---

# dovecot -n  => Below is extract of IMAP configuration
# 1.2.16: /etc/dovecot.conf
# OS: Linux 2.6.18-274.el5PAE i686 CentOS release 5.7 (Final)
log_path: /var/log/dovecot.log
protocols: pop3 pop3s imap imaps managesieve
listen(default): *
listen(imap): *
listen(pop3): *
listen(managesieve): 127.0.0.1:2000
ssl: required
ssl_ca_file: /etc/pki/tls/certs/iRedMail_CA.pem
ssl_cert_file: /etc/pki/tls/certs/iRedMail_CA.pem
ssl_key_file: /etc/pki/tls/private/iRedMail.key
disable_plaintext_auth: yes
login_dir: /var/run/dovecot/login
login_executable(default): /usr/libexec/dovecot/imap-login
login_executable(imap): /usr/libexec/dovecot/imap-login
login_executable(pop3): /usr/libexec/dovecot/pop3-login
login_executable(managesieve): /usr/libexec/dovecot/managesieve-login
last_valid_uid: 500
mail_uid: 500
mail_gid: 500
mail_location: maildir:/%Lh/Maildir/:INDEX=/%Lh/Maildir/
mail_executable(default): /usr/libexec/dovecot/imap
mail_executable(imap): /usr/libexec/dovecot/imap
mail_executable(pop3): /usr/libexec/dovecot/pop3
mail_executable(managesieve): /usr/libexec/dovecot/managesieve
mail_process_size: 1024
mail_plugins(default): quota imap_quota autocreate
mail_plugins(imap): quota imap_quota autocreate
mail_plugins(pop3): quota
mail_plugins(managesieve):
mail_plugin_dir(default): /usr/lib/dovecot/imap
mail_plugin_dir(imap): /usr/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/pop3
mail_plugin_dir(managesieve): /usr/lib/dovecot/managesieve
imap_client_workarounds(default): tb-extra-mailbox-sep
imap_client_workarounds(imap): tb-extra-mailbox-sep
imap_client_workarounds(pop3):
imap_client_workarounds(managesieve):
pop3_client_workarounds(default):
pop3_client_workarounds(imap):
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
pop3_client_workarounds(managesieve):
namespace:
  type: private
  separator: /
  inbox: yes
  list: yes
  subscriptions: yes
namespace:
  type: shared
  separator: /
  prefix: Shared/%%u/
  location: maildir:/%%Lh/Maildir/:INDEX=/%%Lh/Maildir/Shared/%%u
  list: children
  subscriptions: yes
lda:
  postmaster_address: root
  auth_socket_path: /var/run/dovecot/auth-master
  mail_plugins: quota sieve autocreate
  sieve_global_path: /var/vmail/sieve/dovecot.sieve
  log_path: /var/log/sieve.log
auth default:
  mechanisms: plain login
  default_realm: semaphoreindia.com
  user: vmail
  passdb:
    driver: sql
    args: /etc/dovecot-mysql.conf
  userdb:
    driver: sql
    args: /etc/dovecot-mysql.conf
  socket:
    type: listen
    client:
      path: /var/spool/postfix/dovecot-auth
      mode: 438
      user: postfix
      group: postfix
    master:
      path: /var/run/dovecot/auth-master
      mode: 438
      user: vmail
      group: vmail
plugin:
  quota_warning: storage=85%% /usr/local/bin/dovecot-quota-warning.sh 85
  quota_warning2: storage=90%% /usr/local/bin/dovecot-quota-warning.sh 90
  quota_warning3: storage=95%% /usr/local/bin/dovecot-quota-warning.sh 95
  quota: dict:user::proxy::quotadict
  quota_rule: *:storage=0
  expire: Trash 7 Trash/* 7 Junk 30
  expire_dict: proxy::expire
  auth_socket_path: /var/run/dovecot/auth-master
  sieve: /%Lh/sieve/dovecot.sieve
  autocreate: INBOX
  autocreate2: Sent
  autocreate3: Trash
  autocreate4: Drafts
  autocreate5: Junk
  autosubscribe: INBOX
  autosubscribe2: Sent
  autosubscribe3: Trash
  autosubscribe4: Drafts
  autosubscribe5: Junk
  acl: vfile
  acl_shared_dict: proxy::acl
  sieve: /var/vmail/sieve/%Ld/%Ln/dovecot.sieve
  sieve_dir: /var/vmail/sieve/%Ld/%Ln
dict:
  expire: db:/var/lib/dovecot/expire/expire.db
  quotadict: mysql:/etc/dovecot-used-quota.conf
  acl: mysql:/etc/dovecot-share-folder.conf

No mails are coming to our Email from Outside World.
I can Telnet 25 from inside/outside network.
PTR records at ISP end are Ok.

MX PTR => 27.49.39.197,
Firewall NAT IP => 27.49.39.194.

Please help me fix this problem