What is the reason to " Connection time out" whit Postfix??

Hello, I am using Postfix in a OpenSuse box fresh install. This linux is a backup for my domain (NS and MX).  When I try to use this Postfix to send messages I always receive a Conection timed out.

I attached the mail log. Thanks for any help.

Nov  4 23:55:49 ns postfix/smtpd[5168]: connect from localhost[]
Nov  4 23:55:49 ns postfix/smtpd[5168]: 6C7172C0A79: client=localhost[]
Nov  4 23:55:49 ns postfix/pickup[4981]: 724182C0A7E: uid=0 from=<root@ns.abc.org>
Nov  4 23:55:49 ns postfix/cleanup[5157]: 724182C0A7E: message-id=<alpine.LNX.1.10.0811042354520.5159@ns.abc.org>
Nov  4 23:55:49 ns postfix/smtpd[5168]: disconnect from localhost[]
Nov  4 23:55:49 ns postfix/qmgr[3037]: 724182C0A7E: from=<root@ns.abc.org>, size=621, nrcpt=1 (queue active)
Nov  4 23:56:19 ns postfix/smtp[5173]: connect to yahoo.com[]:25: Connection timed out
Nov  4 23:56:31 ns postfix/qmgr[3037]: EC0842C0A7A: from=<root@ns.abc.org>, size=611, nrcpt=1 (queue active)
Nov  4 23:56:49 ns postfix/smtp[5173]: connect to yahoo.com[]:25: Connection timed out
Nov  4 23:56:49 ns postfix/smtp[5173]: 724182C0A7E: to=<baratous@yahoo.com>, relay=none, delay=60, delays=0.07/0.01/60/0, dsn=4.4.1, status=deferred (connect to yahoo.com[]:25: Connection timed out)
Nov  4 23:57:01 ns postfix/smtp[5175]: connect to yahoo.com[]:25: Connection timed out
Nov  4 23:57:31 ns postfix/smtp[5175]: connect to yahoo.com[]:25: Connection timed out
Nov  4 23:57:31 ns postfix/smtp[5175]: EC0842C0A7A: to=<baratous@yahoo.com>, relay=none, delay=19562, delays=19502/0.02/60/0, dsn=4.4.1, status=deferred (connect to yahoo.com[]:25: Connection timed out)
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Bayardo_RivasAuthor Commented:
I forgot to give you my main.cf file:

sendmail_path = /usr/sbin/sendmail
newaliases_path = /usr/bin/newaliases
mailq_path = /usr/bin/mailq
setgid_group = maildrop
manpage_directory = /usr/share/man
sample_directory = /usr/share/doc/packages/postfix/samples
readme_directory = /usr/share/doc/packages/postfix/README_FILES
mail_spool_directory = /var/mail
canonical_maps = hash:/etc/postfix/canonical
virtual_maps = hash:/etc/postfix/virtual
relocated_maps = hash:/etc/postfix/relocated
transport_maps = hash:/etc/postfix/transport
sender_canonical_maps = hash:/etc/postfix/sender_canonical
masquerade_exceptions = root
masquerade_classes = envelope_sender, header_sender, header_recipient
myhostname = abc.org
mydomain = abc.org
mynetworks =
mynetworks_style = subnet
myorigin = $mydomain
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
program_directory = /usr/lib/postfix
relay_domains = abc.org, $mydestination, $mynetworks
inet_interfaces = all
masquerade_domains = abc.org
defer_transports =
disable_dns_lookups = yes
relayhost =
content_filter =
mailbox_command =
mailbox_transport =
smtpd_sender_restrictions = hash:/etc/postfix/access, permit_mynetworks
smtpd_client_restrictions =
smtpd_helo_required = no
smtpd_helo_restrictions =
strict_rfc821_envelopes = no
smtpd_recipient_restrictions = permit_mynetworks,reject_unauth_destination
smtp_sasl_auth_enable = no
smtpd_sasl_auth_enable = no
smtpd_use_tls = no
smtp_use_tls = no
alias_maps = hash:/etc/aliases,hash:/var/lib/mailman/data/aliases
local_recipient_maps = proxy:unix:passwd.byname $alias_maps
mailbox_size_limit = 0
message_size_limit = 10240000
html_directory = /usr/share/doc/packages/postfix/html

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I suspect it's not postfix problem anyhow.

try: telnet yahoo.com 25 # any luck?

Now, verify if Your server's IP is blacklisted on some of those (in)famous dnsbl.
Start from http://www.kloth.net/services/dnsbl.php , google others

Chance setting "disable_dns_lookups" to "no" or comment it. Other wise postfix try to get record "A", not the "MX" one. Check the man.



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Bayardo_RivasAuthor Commented:
Exactly, this is the solution. Once i set "disable_dns_lookups" to "no" everything is working fine.

More info uust for help to others. My server is behind a router and my postfix is a MX backup for my domain.

The "disable_dns_lookups" directive must be set to yes only if you are using other server to send messages.

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