Hi I'm trying to setup webmin+postfix+dovecot+roundcube, for this moment I want things be as simple as possible so I'm using linux users as email accounts.

I can send/receive from the same domain, I mean [email protected] can send/receive to/from [email protected] I tested smtp/imap with outlook and says no problem. if I send a mail from gmail it reject with error of:

Technical details of temporary failure:
The recipient server did not accept our requests to connect.

when I login with roundcube the email address display in the right corner is something like user1@com and I get this error message from logs:

[11-Nov-2012 07:39:03 +0400]: IMAP Error: Login failed for user1 from 187.150.xx.xx. Could not connect to com:143: php_network_getaddresses: getaddrinfo failed: Name or service not known in /var/www/webmail/program/include/rcube_imap.php on line 191 (POST /webmail/?_task=login&_action=login)

it says Could not connect to com:143

looks like it cannot read the domain name.

I used http://mxtoolbox.com/ to check the mx record and it says it can find the server of mail.mydomain.com. I quit sure the problema is from postfix or my server configs, but I have been looking for every config file and cannot find the answer of this. any suggestion I will appreciate.

here are some of my configs (I don't want to make this question too long, I can provide any other information to solve this question):

postfix main.cf

#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# TLS parameters
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtpd_sasl_security_options = noanonymous
smtpd_sasl_auth_enable = yes
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

mydomain = mydomain.com
myhostname = mail.mydomain.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = $mydomain, $myhostname
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
virtual_alias_domains = mydomain.com
smtpd_recipient_restrictions = permit_mynetworks reject_unauth_destination permit_sasl_authenticated
myorigin = $mydomain

roundcube conf

// ---------------------------------- // IMAP // ----------------------------------

$rcmail_config['default_host'] = '%d';
$rcmail_config['default_port'] = 143;
$rcmail_config['imap_auth_type'] = null;
$rcmail_config['imap_delimiter'] = null;
$rcmail_config['imap_ns_personal'] = null;
$rcmail_config['imap_ns_other']    = null;
$rcmail_config['imap_ns_shared']   = null;
$rcmail_config['imap_force_caps'] = false;
$rcmail_config['imap_force_lsub'] = false;
$rcmail_config['imap_force_ns'] = false;
$rcmail_config['imap_timeout'] = 0;
$rcmail_config['imap_auth_cid'] = null;
$rcmail_config['imap_auth_pw'] = null;
$rcmail_config['imap_cache'] = null;
$rcmail_config['messages_cache'] = false;