My Server is sending Registration-Success-Mails to our users. Most of them arrive, but recently one E-Mail to a specific domain remains in the mailq with the following error
(host smtp.geofs.de[5.45.103.59] said:
450 4.7.1 <Ubuntu-1004-lucid64-minimal.localdomain>:
Helo command rejected: Host not found (in reply to RCPT TO command))
Some answers i found here suggested to remove the config parameter "reject_unknown_helo_hostname" in "smtpd_helo_restrictions" but as it turns out my main.cf does not even have "smtpd_helo_restrictions" set. Is there a default value somewhere? Where can i change it? Is there another possible problem-solution?
Here is my current configuration in /etc/postfix/main.cf
# Debian specific: Specifying a file name will cause the first
# line of that file to be used as the name. The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname
smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
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
myorigin = /etc/mailname
mydestination = xxmydomainxx.com, Ubuntu-1004-lucid-64-minimal, localhost.localdomain, localhost, xxmydomainxx.de
relayhost =
mynetworks = 127.0.0.0/8 xxx.xxx.136.32/27
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all
home_mailbox = Maildir/
Is the problem caused by my server or the receiving party server? And how can i fix it?
Love to hear your Ideas, Thanks!