Montando tu server linux

Lo primero, abre una session ssh hacia tu server y pon aqui la salida del comando:
postconf -n
para ver como lo tienes configurado. ojo: postfix es solo para el envio y la recepcion de correos.
como minimo deberas configurar tambien dovecot o courier si quieres acceder a los correos con imap o pop3

la otra cosa es: un servidor en casa ... para correo.... no creo q tus mails lleguen a ninguna parte, ya que los servidores de correo de internet usan blacklists, y el 95% de ips dinamicas de usuario final son descartadas, bloqueadas, marcadas como spam.

Asi que, yo en tu lugar me alquilaria un vps para ello, con una ip mas o menos "fiable" y sin historial spammer. que las ips de usuario final tienen fama de spammer.

Yo para correo en linux usaba esto http://www.iredmail.org incluye bastantes cosas para montar un servidor de correo sin tener que ponerte a instalar los paquetes a mano

webmin? megagoenlaputa menuda basura. Estoy contigo #6

si es solo para administrar el correo y postfixadmin y a correr.

te voy a enseñar uno de mis postconf's

alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
broken_sasl_auth_clients = yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
delay_warning_time = 4
disable_vrfy_command = yes
html_directory = no
inet_interfaces = all
mail_owner = postfix
mailbox_size_limit = 0
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
message_size_limit = 0
milter_default_action = accept
milter_protocol = 2
mydestination = $myhostname, localhost.$mydomain, localhost
mydomain = hurricane-computing.com
myhostname = omicron.hurricane-computing.com
mynetworks = $config_directory/mynetworks
newaliases_path = /usr/bin/newaliases.postfix
non_smtpd_milters = inet:127.0.0.1:8891
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
recipient_delimiter = +
relay_domains = proxy:mysql:/etc/postfix/mysql-relay_domains_maps.cf
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
smtp_tls_CAfile = $smtpd_tls_CAfile
smtp_tls_session_cache_database = btree:$data_directory/smtp_tls_session_cache
smtp_use_tls = yes
smtpd_client_restrictions = 
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_sasl_authenticated,         permit_mynetworks,         reject_unauth_destination,	reject_non_fqdn_sender,        reject_non_fqdn_recipient,         reject_unknown_recipient_domain	,reject_rbl_client zen.spamhaus.org	,reject_rbl_client bl.spamcop.net	,reject_rbl_client dnsbl.sorbs.net
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_path = private/auth
smtpd_sasl_security_options = noanonymous
smtpd_sasl_type = dovecot
smtpd_sender_restrictions = reject_non_fqdn_sender, reject_non_fqdn_recipient
smtpd_tls_CAfile = /etc/ssl/certs/ca-bundle.crt
smtpd_tls_cert_file = /etc/ssl/certs/mail.hurricane-computing.com.crt
smtpd_tls_key_file = /etc/ssl/certs/mail.hurricane-computing.com.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
soft_bounce = yes
tls_random_source = dev:/dev/urandom
transport_maps = hash:/etc/postfix/transport
unknown_local_recipient_reject_code = 550
virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_alias_maps.cf,                     regexp:/etc/postfix/virtual_regexp
virtual_gid_maps = static:12
virtual_mailbox_base = /home/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
virtual_minimum_uid = 101
virtual_transport = dovecot
virtual_uid_maps = static:101

esto es una config funcionando, con Certificado SSL, usando mysql como db para los usuarios, en combinacion con Postfixadmin para administrarlo
Para IMAP/POP3 tengo dovecot.

screenshots postfixadmin
http://postfixadmin.sourceforge.net/screenshots/