server

CentOS 7: Setup a DHCP server and provide specific IP based on MAC address

 in GNU/Linux  tagged CentOS / daemon / DHCP / mac filter / server / static ip by

Step 1: Install DHCP service

We installed the Dynamic host configuration protocol software (DHCP service) using the command:

yum install dhcp;

The dhcp package provides the ISC DHCP service and relay agent.

Step 2: Configure the DHCP service

Afterwards, we created the file /etc/dhcp/dhcpd.conf using the following content:

subnet 192.168.0.0 netmask 255.255.255.0 {
 option routers                  192.168.0.254;
 option subnet-mask              255.255.255.0;
 option domain-name              "bytefreaks.net";
 option domain-name-servers       192.168.0.1;
 option time-offset              -18000;     # Eastern Standard Time
 range 192.168.0.90 192.168.0.99;
}

host coolServer {
 hardware ethernet 0e:e0:4b:b4:28:82;
 fixed-address 192.168.0.80;
}

This configuration allowed us to provide a DHCP service to the network for the subdomain 192.168.0.x with the range [90,99].
Also, we statically defined the IP for our coolServer using a filter based on the MAC address of the machine.
If you do not want to provide any range, only static IPs, then comment out (#) the line that starts with the word range .

Step 3: Start DHCP service

systemctl start dhcpd.service;

Step 4: Check the status of DHCP service

systemctl status dhcpd.service;

It is a good idea to verify that there are no errors, so be sure to check the status of the service.
You can ignore the error that says “you did not define a subnet declaration for all devices” if you do not really need to do it.

Step 5: Permanently enable the DHCP service

systemctl enable dhcpd.service;

Additional:

Disable the DHCP service

systemctl disable dhcpd.service;

Stop the DHCP service

systemctl stop dhcpd.service;

Fedora 25: install / start / enable ssh server

 in GNU/Linux  tagged fedora / openssh-server / server / ssh by

Install

To install the openssh-server, you need to install the openssh-server package:

sudo dnf install -y openssh-server;

Start

To start the sshd daemon (openssh-server) in the current session:

sudo systemctl start sshd.service;

Stop

To stop the active (if any) sshd daemon in the current session:

sudo systemctl stop sshd.service;

Enable

To configure the sshd daemon to start automatically at boot time:

sudo systemctl enable sshd.service;

You will get an output similar to this:

ln -s '/usr/lib/systemd/system/sshd.service' '/etc/systemd/system/multi-user.target.wants/sshd.service'

Disable

To configure the sshd daemon to stop automatic initialization at boot time:

sudo systemctl disable sshd.service;