RHCE Objectives: Network services
Network services are an important subset of the exam objectives. RHCE candidates should be capable of meeting the following objectives for each of the network services listed below:
- Install the packages needed to provide the service
- Configure SELinux to support the service
- Use SELinux port labeling to allow services to use non-standard ports
- Configure the service to start when the system is booted
- Configure the service for basic operation
- Configure host-based and user-based security for the service
- Configure a system to forward all email to a central mail server
Assuming Postfix here vs sendmail (especially with the above article).
Install: yum install postfix
SELinux: Again, with the yum install, the selinux part is already configured.
SELinux Port: See ntp
Configure to start: systemctl enable postfix; systemctl restart postfix;
Configure the service for basic operation: This may be the first block below (the myhostname to mydestination).
Configure host-based and user-based security for the service:
Configure a system to forward all email to a central mail server:
Here we don’t know if there is a central mail server already or if one will be provided. Assuming “send mail to the following IP address or server”
In /etc/postfix/main.cf uncomment/change the following lines:
myhostname = server.example.com mydomain = example.com myorigin = $mydomain inet_interfaces = loopback-only mydestination = relayhost = 192.168.1.1
The first parts are to configure your system. Blank mydestination and set relayhost. This will forward mail to the relayhost.