A firewall block everything.it depends on you when configuring your network wat traffic to let in and wat traffic to block.its acts as a gaurd to u r network.its like a screening of a person on a airport...its does a deep pack inspection.
When no MTA is installed, How to send an email with a cronjob? I have below entry in my cronjob? My /etc/cron.d/backup file looks like this.
MAILTO=myemail@example.com 15 11 * * * root /root/scripts/backup.sh
Can I send this email via SMTP server?