can not send mail by port 25 but can with SSL on port 465

senzacionale asked:

netstat -tunlp | grep :25
(No info could be read for "-p": geteuid()=1000 but you should be root.)
tcp        0      0    *               LISTEN      -
tcp6       0      0 :::25                   :::*                    LISTEN      -

i am having problem sending mails with postfix. I can send it by SSL and port 465 but not with port 25. When I use port 25 i can’t get any error in /var/log/mail.log or mail.err

Port is opened:

telnet 25
Connected to
Escape character is '^]'.
220 ESMTP Postfix

when i send by roundcube mail i get this:

Jul 15 10:06:07 ubuntu-server postfix/smtpd[9272]: lost connection
after UNKNOWN from localhost[] Jul 15 10:06:07 ubuntu-server
postfix/smtpd[9272]: disconnect from localhost[]

generally error

SMTP Error (-1): Connection to server failed


my /etc/hosts      localhost        ubuntu-server

what can be wrong? Is etc/hosts correct?

My answer:

Most likely your Internet Service Provider is blocking outgoing connections on port 25. This is very common with residential cable and ADSL connections.

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