Hallo gan, ane newbie nih pengen belajar ngoprek ubuntu,
ane bikin mail server pake postfix, dovecot nah ane ga bisa ngirim email ke gmail, error report dari mail nya kayak gini...

This is the mail system at host mail.example.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<ekekrockstar@gmail.com>: host gmail-smtp-in.l.google.com[74.125.68.26] said:
550-5.7.1 [128.199.208.68] The IP address sending this message does not
have a 550-5.7.1 PTR record setup. As a policy, Gmail does not accept
messages from 550-5.7.1 IPs with missing PTR records. Please visit
550-5.7.1 https://support.google.com/mail/answ...authentication for
more 550 5.7.1 information. h132si10329649pfc.175 - gsmtp (in reply to end
of DATA command)

mudah2an ada yang bisa bantu....