Use discovered IPv4 address

roles/common/templates/etc_fail2ban_jail.local.j2

 [DEFAULT]
-ignoreip  = 127.0.0.1 {{ server_ip_address }}
+ignoreip  = 127.0.0.1 {{ ansible_default_ipv4.address }}
 bantime   = 86400
 destemail = {{ admin_email }}
 banaction = iptables-multiport

roles/mailserver/tasks/checkrbl.yml

   get_url: url=https://raw.github.com/lukecyca/check-rbl/f6b222b0ca/check-rbl.pl dest=/opt/check-rbl.pl
 
 - name: Install nightly check-rbl cronjob
-  cron: name="check-rbl" hour="2" minute="0" job="perl /opt/check-rbl.pl -i ${server_ip_address}"
+  cron: name="check-rbl" hour="2" minute="0" job="perl /opt/check-rbl.pl -i {{ ansible_default_ipv4.address }}"

roles/mailserver/templates/etc_opendkim_TrustedHosts.j2

 127.0.0.1
-{{ server_ip_address }}
+{{ ansible_default_ipv4.address }}
 {% for domain in mail_virtual_domains %}
 {{ domain.name }}
 {% endfor %}

vars/defaults.yml

 # main_user_name: (required)
 admin_email: "{{ main_user_name }}@{{ domain }}"
 # encfs_password: (required)
-# server_ip_address: (required)
 
 # ircbouncer
 znc_version: 1.0

vars/user.yml

 domain: TODO.com
 main_user_name: TODO
 encfs_password: TODO
-server_ip_address: TODO
 
 # ircbouncer
 irc_nick: TODO