Icinga is installed and working properly.
The system will send an e-mail if one of the monitored devices or services is something wrong.
A 'simple' solution is it to install 'qpopper' to retriieve e-mails from the local user itself. That worked in a test immediately. The obvious drawback is that it depends on the retrieving the e-mail if and when the message is known about a problem.
The better way st it to configure the system in a way that Icinga sends a message itself to the mail server of the domain and windows domain. I did it with Postfix. The configuration is similar to that which is described in the instructions to a mail relay on this website here.
Input:
# apt-get install postfixIf asked choose Internet-Site.
Example: /etc/postfix/main.cf
# See /usr/share/postfix/main.cf.dist for a commented, more complete version
# 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 $mail_name (Debian/GNU)
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
readme_directory = no
# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.
# deaktivating myhostname, using mydomain, main.cf can be used more flexible
# mac be copied on different computer.
# Postfix istself looks for myhostname in the system
#myhostname = icinga.domainname.local
mydomain = domainname.local
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
#myorigin = /etc/mailname
myorigin = $mydomain
# changed mydestination - final determination of the emails
# mydestination = mailrelay.domainname.local, localhost.domainname.local, , localhost
mydestination = $mydomain
$myhostname
relayhost = [123.123.123.123]
mynetworks = 123.123.123.123/32,
127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_command = procmail -a "$EXTENSION"
mailbox_size_limit = 0
recipient_delimiter = +
#inet_interfaces = loopback-only
inet_interfaces = all
# the transport file has to be configured seperatly.
transport_maps = hash:/etc/postfix/transport
unknown_local_recipient_reject_code = 550
relay_domains = domainname.de
Postfix has to know to which internal mail server the e-mails shoul be forwarded. Here the domain name (domainname.de) is specified as found on the Internet.
Input:
# touch /etc/postfix/transport
Content in the first line of this file:
domainname.de smtp:[ip-address]
The brackets [] have to be in the file.
Creating the transport.db.
Input:
# postmap hash:/etc/postfix/transport
Sure, there will be a problem if icinga or the mailserver himself don't work correct.
# /etc/init.d/postfix reload