Crontab emails

The mail sent by your server’s cron jobs are refused by the recipient server due to: Crontab will by default send from $LINUX_USER@$HOSTNAME. You can change this by connecting to the server via SSH, running “crontab -e”, and adding “MAILFROM=VALID_ADDRESS_HERE”. Ideally, the MAILFROM will be set to a mail account hosted on your server, but … Read more

Email Administration for Postfix , Plesk and Qmail

Basics
rDNS (Reverse DNS)

The Reverse DNS for an IP should be set to the EHLO value that is sent in the outgoing mail header. This is generally the HostName of the computer.

This value should also match the outgoing IP address used to send the mail.

On a multi-IP server, if the sending IP does not match the EHLO domain, you may be sending from Postfix. Switching to Qmail may cause the sending IP to match the primary IP on the server, which should correct any mis-matched IP/EHLO issues.

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Add port 80 to firewalld CentOS 7

By default the port 80 for http connection is filtered on Redhat 7 as you can only access this port from the actual localhost and not from any other public host. To open a port 80 on RHEL 7 Linux we need to add an iptables rule. For this RHEL7 uses firewall-cmd. First add your … Read more