Install SSH Server on Linux (Debian, Ubuntu, Fedora, CentOS, RedHat)

Debian / Ubuntu

sudo apt-get install -y openssh-server

RPM based Distros, Fedora / CentOS / RedHat

sudo dnf install -y openssh-server

or use yum

sudo yum install -y openssh-server

Start ssh service

sudo systemctl start sshd

By default the SSH service should start when the system starts, but if not try the following command to enable the service on boot up.

Debian / Ubuntu

systemctl enable ssh

Fedora, CentOS, RedHat

systemctl enable ssh

Change SSH port

Not necessary, but it is a good idea to change the default ssh port.  To change the port edit the sshd file.

vi /etc/ssh/sshd_config

How To export private SSH key on Linux

All that needs to be done is the “id_rsa” key needs to be copied to the “new” host.  You can do this with SCP or sftp.

Example with SCP

The following examples are showing how to export a RSA private key, if your using DSA, then replace id_rsa with id_dsa.

Copy private key from remote server to local machine for the local user

scp root@192.168.1.1:~/.ssh/id_rsa ~/.ssh/

Copy private key from localhost to remote host.  This command copies the local users private key to the root user @ 192.168.1.1

scp ~/.ssh/id_rsa root@192.168.1.1:~/.ssh/

 

Allow SSH access from a specific host using hosts.allow and hosts.deny on Linux

This is just a quick write on the hosts.allow and deny files.  You can lookup “spawn” and/or “twist” for some advanced usage.

 

So to limit an IP address, or a IP range access to SSH, do the following

Deny all incoming request for SSH

Edit the “hosts.deny” file

vi /etc/hosts.deny

add the following line

sshd : ALL

Now edit “hosts.allow” and allow the client IP, or IP range to access SSH

vi /etc/hosts.allow

add the following line to allow a single IP

sshd : 192.168.1.182

If you want to allow the whole subnet, then replace the above line with this one

sshd : 192.168.1.

hosts.allow overrides hosts.deny.  So you deny everything and then allow exceptions.

Setting up MySQL for FreeRadius

Install Mysql

yum install mariadb mariadb-server freeradius-mysql

Setup MySQL database.

mysql -u root -p
CREATE DATABASE radius;
GRANT ALL ON radius.* TO radius@localhost IDENTIFIED BY "RadiusPassword";
exit

Import the schema.sql file into the db.

mysql -u radius -p radius < /etc/raddb/mods-config/sql/main/mysql/schema.sql

Should be good to go.

Install VirtualBox Guest Additions for Fedora 22

Install kernel headers, dkms, etc

dnf -y kernel-headers kernel-devel dkms gcc gcc-c++

Reboot the VM

reboot

Mount the Guest Additions by going to menu > Devices > Insert Guest Additions CD image… or you can hit “Host + D”.

The Host key is typically the Right Ctrl(On Windows) or CMD(On OS X) key.

 

Installing the Guest Additions

Via the GUI

Mount the Guest Additions from your file browser, and then launch the “VBoxLinuxAdditions.run”.

You will need root privileges, so either launch your file browser as root, or drag and drop the “VBoxLinuxAdditions.run”, into a root terminal and hit Enter.

Via Command Line

mkdir /tmp/vbox
sudo mount /dev/cdrom /tmp/vbox
sudo /tmp/vbox/VBoxLinuxAdditions.run

If you run into any errors, try ejecting, and remounting the Guest Additions cd.

Install Wireless Broadcom Driver for Fedora 21

Run the following commands as root

rpm -Uvh http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm
rpm -Uvh http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm

Update the system and then download the driver.

yum update
yum install kmod-wl

When the above commands finish reboot the computer

reboot

How to View Installed Programs in linux

Debian Based Distros

The below command should work for Debain, Ubuntu, and the Raspberry Pi Raspbian.

dpkg --get-selections

 

RPM Based Distros

The following works on Fedora, CentOS, ReHat.

rpm -qa

 

The above commands return all of the packages installed on a system.  If you want to look for a specific program or package you can use grep to filter the results.

rpm -qa | grep program

or

dpkg --get-selections | grep program

How to set a static ip address on CentOS, Fedora, or Red Hat Linux

Open up the following file with your favorite text editor. Change eth0 to the interface you need, like “wlan0” or “eth1”.

 vi /etc/sysconfig/network-scripts/ifcfg-eth0

The file should look something like the following.

DEVICE=eth0
HWADDR=0A:2G:F3:56:66:4B
TYPE=Ethernet
UUID=aeh9421c-6a62-712c-886d-347813g8d1dh
ONBOOT=no
NM_CONTROLLED=yes
BOOTPROTO=dhcp

To set the static IP address change “BOOTPROTO=dhcp” to “BOOTPROTO=static” and add the following to the end of the file. If you want/need the interface to come up when the computer boots up then be sure to change “ONBOOT=no” to “ONBOOT=yes”.

BROADCAST=192.168.1.255
DNS1=8.8.8.8
GATEWAY=192.168.1.1
IPADDR=192.168.1.110
NETMASK=255.255.255.0

So your file should now look like this.

DEVICE=eth0
HWADDR=0A:2G:F3:56:66:4B
TYPE=Ethernet
UUID=aeh9421c-6a62-712c-886d-347813g8d1dh
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=static
BROADCAST=192.168.1.255
DNS1=8.8.8.8
GATEWAY=192.168.1.1
IPADDR=192.168.1.110
NETMASK=255.255.255.0

Save the file and restart networking.

service network restart

Finally, check you IP address with ifconfig.

root@localhost ~]# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 0A:2G:F3:56:66:4B  
          inet addr:192.168.1.110  Bcast:192.168.1.255  Mask:255.255.255.0