i have configured fetchmail to deliver fetched mails to user mailbox.

Here is my output of postconf -n:

root@mailserver:~# postconf -n
alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases
allow_min_user = no
allow_percent_hack = no
append_dot_mydomain = no
biff = no
bounce_queue_lifetime = 4h
broken_sasl_auth_clients = yes
config_directory = /etc/postfix
content_filter = smtp-amavis:[127.0.0.1]:10024
delay_warning_time = 0h
disable_vrfy_command = yes
dovecot_destination_recipient_limit = 1
enable_original_recipient = no
home_mailbox = Maildir/
inet_interfaces = all
inet_protocols = ipv4
mailbox_command = /usr/lib/dovecot/deliver
mailbox_size_limit = 0
maximal_backoff_time = 4000s
maximal_queue_lifetime = 4h
message_size_limit = 31457280
minimal_backoff_time = 300s
mydestination = $myhostname, localhost, localhost.localdomain, localhost.$myhostname
mydomain = albawardi.com
myhostname = mailserver.albawardi.com
mynetworks = 127.0.0.0/8
mynetworks_style = host
myorigin = mailserver.albawardi.com
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_run_delay = 300s
readme_directory = no
recipient_bcc_maps = proxy:ldap:/etc/postfix/ldap/recipient_bcc_maps_user.cf, proxy:ldap:/etc/postfix/ldap/recipient_bcc_maps_domain.cf
recipient_delimiter = +
relay_domains = $mydestination, proxy:ldap:/etc/postfix/ldap/relay_domains.cf
relayhost = 216.25.6.131
sender_bcc_maps = proxy:ldap:/etc/postfix/ldap/sender_bcc_maps_user.cf, proxy:ldap:/etc/postfix/ldap/sender_bcc_maps_domain.cf
smtp-amavis_destination_recipient_limit = 1
smtp_data_init_timeout = 240s
smtp_data_xfer_timeout = 600s
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options =
smtp_tls_CAfile = $smtpd_tls_CAfile
smtp_tls_security_level = may
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
smtpd_data_restrictions = reject_unauth_pipelining
smtpd_end_of_data_restrictions = check_policy_service inet:127.0.0.1:10031
smtpd_helo_required = yes
smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, check_helo_access pcre:/etc/postfix/helo_access.pcre
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unlisted_recipient, check_policy_service inet:127.0.0.1:7777, check_policy_service inet:127.0.0.1:10031, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_reject_unlisted_recipient = yes
smtpd_reject_unlisted_sender = yes
smtpd_sasl_auth_enable = yes
smtpd_sasl_authenticated_header = no
smtpd_sasl_local_domain =
smtpd_sasl_path = ./dovecot-auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_login_maps = proxy:ldap:/etc/postfix/ldap/sender_login_maps.cf
smtpd_sender_restrictions = permit_mynetworks, reject_sender_login_mismatch, permit_sasl_authenticated
smtpd_tls_CAfile = /etc/ssl/certs/iRedMail_CA.pem
smtpd_tls_cert_file = /etc/ssl/certs/iRedMail_CA.pem
smtpd_tls_key_file = /etc/ssl/private/iRedMail.key
smtpd_tls_loglevel = 0
smtpd_tls_security_level = may
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtpd_use_tls = yes
swap_bangpath = no
tls_random_source = dev:/dev/urandom
transport_maps = proxy:ldap:/etc/postfix/ldap/transport_maps_user.cf, proxy:ldap:/etc/postfix/ldap/transport_maps_domain.cf
virtual_alias_domains =
virtual_alias_maps = proxy:ldap:/etc/postfix/ldap/virtual_alias_maps.cf, proxy:ldap:/etc/postfix/ldap/virtual_group_maps.cf, proxy:ldap:/etc/postfix/ldap/virtual_group_members_maps.cf, proxy:ldap:/etc/postfix/ldap/catchall_maps.cf
virtual_gid_maps = static:2000
virtual_mailbox_base = /var/vmail
virtual_mailbox_domains = proxy:ldap:/etc/postfix/ldap/virtual_mailbox_domains.cf
virtual_mailbox_maps = proxy:ldap:/etc/postfix/ldap/virtual_mailbox_maps.cf
virtual_minimum_uid = 2000
virtual_transport = dovecot
virtual_uid_maps = static:2000

Please check and let me know my configurations are right or need any changes?

regards,
Shaik

*) Why "mailbox_size_limit = 0" in Postfix?

I dint set to zero, i think its by default. Please let me know what i have to configure the limit?  ( from admin-pro panel its showing 100MB to all users since i have set to 100MB by default to all users) and also please see my above output and let me know what changes it needs because i dont want to take risk since all my company emails are depending on this server.

*) Also, how does fetchmail deliver email to mailbox? Does fetchmail deliver mail to mailbox directly by itself, or pipe to other program (like Dovecot LDA)?

It delivers directly to mailbox. is it ok?

Thanks for your asusual quick support.

regards,
Shaik

Great..!!! Now i have set my fetchmail limit to 25MB (26214400) in fetchmail config file (fetchmailrc).

fetchmailrc;
------------------------------------------------------------------------------------------------------------------
postconf -e "message_size_limit = 26214400"
------------------------------------------------------------------------------------------------------------------
& in Postfix
-------------------------------------------------------------------------------------------------------
mailbox_size_limit = 104857600
message_size_limit = 31457280
-------------------------------------------------------------------------------------------------------

well, is their any configuration in fetchmail to fetch all pop3 accounts at the same time instead of one by one? because we have more than 300 pop3 accounts to poll and its taking very long time.
or should i open new support request?

Thanks in advance Zhang.

regards,
Shaik