Allow KDE Connect through firewall

Firewalld

sudo firewall-cmd --zone=public --permanent --add-port=1714-1764/tcp
sudo firewall-cmd --zone=public --permanent --add-port=1714-1764/udp
sudo systemctl restart firewalld.service

UFW firewall

sudo ufw allow 1714:1764/udp
sudo ufw allow 1714:1764/tcp
sudo ufw reload

More information https://community.kde.org/KDEConnect

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.

How to Set a Static IP Address on a Raspberry Pi

The examples given here are for modifying the wlan0 interface.  Replace wlan0 with the interface you are configuring. i.e. (eth0,wlan1)

Method 1

This was the typical way to add a static IP address to a Pi, if you have issues with this, then try Method 2.

sudo vi /etc/network/interfaces

In the file it is pretty easy to see which lines control which interface, find the lines that control wlan0 (or the interface your configuring) and change/add to look like below.

iface wlan0 inet static
address 192.168.42.109
netmask 255.255.255.0
gateway 192.168.42.1

Save the file, reboot, and the Pi should come up with the new static IP.

Method 2

It looks like on the newer versions of Raspbian, the above method does not work anymore, so now you have to edit the following file

sudo vi /etc/dhcpcd.conf

and add the following lines.

interface wlan0
static ip_address=192.168.42.109/24
static routers=192.168.42.1
static domain_name_servers=192.168.42.1

If you just need to assign a static IP address, to the device, because it is going to be setup as a hotspot or something, you can get away with the following.

interface wlan0
static ip_address=192.168.42.1/24

If you run into issues with it not assigning the address, check the /etc/network/interfaces file and make sure that the line that starts with “iface wlan0” says manual at the end and not static.  If it says “iface wlan0 inet static”, change it to “iface wlan0 inet manual”

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

Also, on some newer versions of CentOS you may need to add NM_DISABLED=no

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

 

How to set a Static IP Address in Ubuntu and Debian

The first thing we need to do, is open our interfaces file.  Execute the following from a terminal.

sudo vi /etc/network/interfaces

or

sudo nano /etc/network/interfaces

Then add or copy and paste the following.

auto eth0
iface eth0 inet static
        address 192.168.1.100
        netmask 255.255.255.0
        network 192.168.1.0
        broadcast 192.168.1.255
        gateway 192.168.1.1

Close the file. Now we need to change the DNS settings

sudo vi /etc/resolv.conf

or

sudo nano /etc/resolv.conf

Edit the nameserver line to something like the following.

nameserver 8.8.8.8

Close the file and then restart the networking stuff.

sudo /etc/init.d/networking restart

How to Open a Port on Redhat, CentOS or Fedora Linux

By default iptables firewall stores its configuration at /etc/sysconfig/iptables file. You need to edit this file and add rules to open port number.

Note: if you have SELinux  enabled, you’ll need to allow the port with semanage.

Open port 80

To open a different port just enter the port number.

Open flle /etc/sysconfig/iptables:

# vi /etc/sysconfig/iptables

Append rule as follows:

A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT

Save and close the file.  Restart iptables:

# /etc/init.d/iptables restart

or,

#service iptables restart

 

Verify that port is open

Run the following command:

netstat -tulpn | less

Make sure iptables is allowing the port you enabled:

iptables -L -n

If you need more info you can refer to the man page:

man iptables