Fix iptables for outgoing email

roles/iptables/templates/rules.v4.j2

@@ -37,6 +37,7 @@ COMMIT
 -A INPUT -m state --state NEW -m tcp -p tcp -s 81.95.52.102 --dport 4949 -j ACCEPT
 # The following rule is for mx.webarch.net
 -A INPUT -m state --state NEW -m tcp -p tcp -s 81.95.52.71 --dport 25 -j ACCEPT
+-A INPUT -m state --state NEW -m tcp -p tcp -s {{ app_ip_address.stdout }} --dport 25 -j ACCEPT
 -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
 -A INPUT -d 127.0.0.0/8 ! -i lo -j REJECT --reject-with icmp-port-unreachable
 -A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT