Current File : //usr/lib/firewalld/services/smtp.xml
<?xml version="1.0" encoding="utf-8"?>
<service>
<short>Mail (SMTP)</short>
<description>This option allows incoming SMTP mail delivery. If you need to allow remote hosts to connect directly to your machine to deliver mail, enable this option. You do not need to enable this if you collect your mail from your ISP's server by POP3 or IMAP, or if you use a tool such as fetchmail. Note that an improperly configured SMTP server can allow remote machines to use your server to send spam.</description>
<port protocol="tcp" port="25"/>
</service>