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Speed up shutdown time using regedit

When you shut down your PC, Windows gives a bit of time to running applications to save their data before it force closes them. This ensures that no unsaved app data is lost and no app functions get corrupted due to force stopping in the middle of working.

However, if faster shutdown matters to you and you have the good habit of closing all apps and saving data before you shut down, then you can decrease this timer to speed up shutdown.

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How to Test Open Ports in Linux

Whether you are troubleshooting network connectivity issues or configuring a firewall, one of the first things to check is what ports are actually opened on your system.

View the listening ports with the netstat command:

netstat -lntu

Viewing open ports with the netstat command.

The output above shows the port 8080 is opened.

List the open sockets with the ss command:

ss -lntu

The port appears as part of the socket.

Viewing open ports with the ss command.

Test the port by specifying its number to the nmap command.

nmap localhost -p 8080

Using the nmap command to see port status in linux.
Test the Port with the Netcat Utility

The Netcat tool features the nc command that you can use to test an open port. To do so:

1. Use a command such as echo to pipe output to Netcat and specify the port to listen to. The example below pipes a message to test port 8

echo “Testing port 8080” | nc -l -p 8080

2. Leave the command running and open another terminal window.

3. In that terminal window, use a command such as telnet to query the local socket.

telnet localhost 8080

If the port is open, the output of the telnet command contains the message piped to nc in step 1.

Using the telnet command to probe a port in Linux.

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How to Open a Port in Linux

The port number is a virtual concept in computer networking that provides a network identifier for a service or application. The number is a 16-bit integer from 0 to 65535 that combines with the IP address to create a network communication socket.

Prerequisites

  • Administrative system access.
  • Access to the terminal.
Listing Open Ports

Before opening a port on a system, check if the port you need is already open. The simplest way to do this is to pipe the output of the netstat command to the grep command.

netstat -na | grep :[port-number]

The syntax above tells grep to look for a specific port number in the port list provided by netstat. For example, to check if port 8080 is available on the system, type:

netstat -na | grep :8080

If the port is closed, the command returns no output.

Alternatively, use the following netstat command to display a list of listening ports:

netstat -lntu

The -l option looks for the listening ports, -n provides numerical port values, while -t and -u stand for TCP and UDP, respectively.

Listing open ports in Linux.
Opening a Port in Linux

The correct procedure for opening a port depends on the Linux distribution and the firewall you are using. The following sections provide steps for the three most common scenarios:

  • The UFW firewall on Ubuntu-based distributions.
  • firewalld on CentOS and other RHEL-based distributions.
  • The iptables utility for the systems without UFW and Firewalld.
Ubuntu and UFW Based Systems

UFW (Uncomplicated Firewall) for Ubuntu allows you to open a port with a single command:

sudo ufw allow [port-number]

Opening a port in Ubuntu with UFW.

Alternatively, open the port used by a specific service without stating the port number:

sudo ufw allow [service-name]

Note: After you finish creating the rules, ensure UFW is active on your system by typing:

sudo ufw enable
CentOS and Other Systems with firewalld

The firewalld tool on CentOS, Fedora, and other related distributions, enables users to control port access on their system. The following command opens a specific port:

sudo firewall-cmd –zone=public –add-port=[port-number]/[protocol] –permanent

Opening a port on RHEL based systems with firewalld.

Note: The --zone=public argument is necessary only in multi-zone system configurations. By default, firewalld assigns all interfaces to the public zone.

Linux Distributions without UFW or firewalld

While installing a full-fledged firewall is the recommended way of maintaining system security, some Linux distributions still use the legacy iptables solution. The iptables utility allows configuring rules to filter IP packets using the Linux kernel firewall.

Use the following command to create an iptables rule for opening a port:

sudo iptables -A INPUT -p [protocol] –dport [port] -j ACCEPT

The command creates an IPv4 rule. To create an IPv6 rule, use the ip6tables command:

sudo ip6tables -A INPUT -p [protocol] –dport [port] -j ACCEPT

The port number is specified with the --dport option. The -p flag allows you to define the protocol (tcp or udp). For example, to create an IPv4 rule for the TCP port 8080, type:

sudo iptables -A INPUT -p tcp –dport 8080 -j ACCEPT

Make iptables Rules Persist on Debian-Based Systems

The rules created using iptables do not persist after reboots.

Follow the steps to restore iptables rules after a reboot on Debian-based systems:

  • Save the IPv4 rules you created:

iptables-save > /etc/iptables/rules.v4

  • Store any IPv6 rules in a separate file:

ip6tables-save > /etc/iptables/rules.v6

  • Install the iptables-persistent package:

sudo apt install iptables-persistent

This package automatically reloads the contents of the rules.v4 and rules.v6 files when the system restarts.

Make iptables Rules Persist on RHEL-Based Systems

RHEL-based systems store the iptables configuration in a different location. Type the commands below to save the IPv4 and IPv6 rules, respectively:

iptables-save > /etc/sysconfig/iptables

ip6tables-save > /etc/sysconfig/ip6tables

  • Ensure the iptables-services package is installed:

sudo dnf install iptables-services

  • Start the service:

sudo systemctl start iptables

  • Enable the service:

sudo systemctl enable iptables

  • Save the iptables rule:

sudo service iptables save

Saving the iptables configuration.

Restart the service to enforce the rule:

sudo systemctl restart iptables

Opening a port can be helpful for various reasons, such as allowing incoming traffic to access a specific service or application on your system.

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Cum recuperam datele dintr-un telefon Android

Avem mai multe situatii in care se mai intampla sa pierdem datele de pe telefonul nostru cu sistem Android. Exista mai multe metode pentru a recupera datele pierdute.

  • Pentru a recupera datele unui telefon cu sistem Android vom folosi programul Eassiy Android Data Recovery. Acesta are o rata mare de recuperare a datelor penstru sistemul Android atat pentru foto și video, suporta majoritatea dispozitivelor Android, inclusiv Samsung, Huawei, HTC, Google, LG, si Sony
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