I'm trying to sending email from nagios monitoring to some email addresses. But I have a problem with setup my from domain when I'm sending an email every time my from email address seems like this:    from=&lt;root@patrik-VirtualBox&gt;   and format like this some mail servers are rejecting.  so I need replace @patrik-VirtualBox to my domain @onedata.sk  here is my /etc.postfix/main.cf:  alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases append_dot_mydomain = no biff = no config_directory = /etc/postfix home_mailbox = Maildir/ inet_interfaces = all mailbox_command = mailbox_size_limit = 0 mydestination = mail.onedata.sk, localhost.localdomain, localhost, yourdomain.com myhostname = onedata.sk mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 readme_directory = no recipient_delimiter = + relayhost = smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtpd_use_tls = yes   from log:  Feb  3 01:55:56 patrik-VirtualBox postfix/pickup[10655]: E2FFA66C36: uid=0 from=&lt;root@patrik-VirtualBox&gt; Feb  3 01:55:56 patrik-VirtualBox postfix/cleanup[10963]: E2FFA66C36: message-id=&lt;20150203005556.E2FFA66C36@onedata.sk&gt; Feb  3 01:55:56 patrik-VirtualBox postfix/qmgr[10656]: E2FFA66C36: from=&lt;root@patrik-VirtualBox&gt;, size=340, nrcpt=1 (queue active) Feb  3 01:56:35 patrik-VirtualBox postfix/smtp[10965]: E2FFA66C36: to=&lt;patrik.kristel@onedata.sk&gt;, relay=mailhub.nextra.sk[195.168.1.42]:25, delay=38, delays=0.03/0.01/30/8, dsn=5.0.0, status=bounced (host mailhub.nextra.sk[195.168.1.42] said: 517 Syntax error. (in reply to MAIL FROM command))   I have also tried to set up relayhost or , but it didn't help.  I have configured it in another server like this and there it works fine, so I don't understand why it doesn't work.
Hi currently Nagios sends notifications from nagios@server.domain.com, How do I go about configuring this? Thanks
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