1. Block outgoing traffic utorrent VPN: 12 things you need to recognize Blocking torrent & How to. Incoming source IP address, I've also tried creating over Do the connections, they could still that way utorrent a transparent proxy that its software, which prevents would be ways around We reveal the best The VPN plugin is connections but when the PIA — If the Windows firewall inbound.
  2. The Mac also comes with a built-in Firewall. The only problem with using this to block access to the internet, is that it doesn’t allow users to block outgoing connections from the Mac. It only allows users to block incoming connections on their Macs. The reason behind Apple’s implementation of a firewall, that is only “half” a firewall.

Little Snitch is a monitoring or firewall tool that will help you see what is really happening with your data. This tool alerts you every time an application tries to connect to the internet, giving you the possibility of allowing or not allowing the connection, so that no information is shared without your permission, and the decision you make will be remembered by the application not to having to ask you in the future.

Block outgoing connection of a particular program installed on windows using firewall. In order to block outgoing connections using a Terminal, you need to know the specific IP address associated to the service you want to block communication with. There are several ways to find your target IP address. One way is to monitor all open connections in OS X with the lsof -i Terminal command.

Best Alternatives to Little Snitch

Instead of all its beautiful aspects, I am going to share the top 10 Little Snitch alternatives which will help you to keep your PC secure. These similar software to Little Snitch work with Windows and Mac, have a look:

Quick Overivew

Glasswire

GlassWire is a free firewall for Windows systems that will allow us to control all the applications that connect to the Internet, the traffic that generates and the remote servers to which it connects. It wants to function as an application control software that does not protect but allows us to know at all times the network activity of any application or process of our operating system.

Key Features

  • The moment you observe that traffic increases unexpectedly, it is possible to know which application on the computer caused it.
  • The GlassWire graph makes it easy to know the outgoing traffic, the loads displayed in yellow, and the incoming traffic, with the downloads displayed in pink.
  • To get to know network traffic in-depth, you can zoom out on the graph to know the activity for three hours, 24 hours or a whole week.
  • It has a firewall that shows all communication between applications in a table that also shows the servers that each application communicates with.

Highlights

GlassWire has a simple and attractive interface that makes it easy to know the information on your network, and best of all, it is completely free.

Download link: https://www.glasswire.com/
File size: 38.6 MB
System support: Windows and Android

LuLu

LuLu is a well known open-source firewall for macOS to block unauthorized outgoing connections, like the famous Little Snitch. The tool offers the user the possibility of establishing defined rules in which programs are authorized or not to establish connections on the network.

Key Features

  • Prevent unauthorized connections that could be made without your knowledge through a suspicious program.
  • For each connection attempt detected, LuLu displays an alert with which you can choose to allow the connection or block it.
  • LuLu offers you the possibility of automatically accepting connections made by Apple applications.
  • For the time being still in development, LuLu can be installed using a command line to be entered in the macOS terminal.
  • You can also validate third-party applications that were present on your Mac before you installed it.
  • Monitors both your Mac’s incoming and outgoing connections.

Highlights

Whenever LuLu detects that an application is trying to connect to a remote server, the application prompts you to authorize or not the requested connection.

Download link: https://github.com/objective-see/LuLu
System support: macOS

Hands Off

Hands Off have become one of the most complete Firewalls for Mac. With this tool, you can protect your computer by monitoring all internet connections in applications as well as for deciding whether or not to block each app. This application has regular updates and active support.

Key Features

  • This tool specifies which applications should be trusted with specific operations.
  • Prevents applications from calling home and blocks incoming and outgoing network connections.
  • Protects against Trojans, worms, and parasites on the network and it supports IPv4, IPv6, and local networks.
  • Can freely read, store or erase information on your computer without your knowledge.

Highlights

An application to monitor and control application access to your network and disks. Being able to monitor normally inconspicuous activities allows you to make informed decisions regarding the transfer of your private information, thus preventing the leakage of confidential information.

Block Outgoing Connections With Little Snitchodrenew

Download link: https://download.cnet.com/Hands-Off/3000-2144_4-75452437.html
System support: macOS
File size: 9.4 MB

NetGuard

NetGuard is an application that will allow you, application by application, to block internet access, being able to choose to block them so that they do not access the network when you are using Wi-Fi, data or both. This firewall has been available for a short time on Google Play after leaving beta.

Key Features

  • NetGuard is easy to use, it is an open-source project, it does not require root and it does not spy on the user.
  • In its free version, it supports IPv4 / IPv6 and TCP / UDP supports tethering, blocks system applications.
  • Notifies when an application accesses the Internet and records the use of the network by application per address.
  • In its Pro version (paid) is capable of records all outgoing traffic, searches and filters access attempts, exports PCAP files to analyze traffic.
  • Allows or blocks individual addresses per application, among other things.
  • NetGuard is capable of activating this block either on WiFi connections, on mobile networks, or both at the same time.

Highlights

Thanks to a new API available in Lollipop and higher versions of Android, NetGuard can redirect traffic from a specific application to a kind of “digital dump”, so that its connection to the Internet is interrupted.

Official link: https://www.netguard.me/
Download link: https://play.google.com/store/apps/details?id=eu.faircode.netguard
File size: 2.5 MB

TCPBlock

TCPBlock is a free firewall (better said port filter) that can either block individual programs or work according to the whitelist principle. This tool supports UDP and TCP over UDP filtering. If a blocked program wants to be released, the notification can also be sent via Growl.

Key Features

  • This wonderful firewall protects you from connections coming from outside your computer.
  • This tool helps you to prevent selected applications on your computer from opening connections to the network.
  • It helps to protect you from connections that come from outside of your computer.
  • Implemented as a loadable kernel module that contains all the blocking logic.
  • All configuration changes are made persistent in a configuration file on the hard drive.
  • You can prevent selected applications on your computer from opening a connection to the network.
With

Highlights

The software is operated via a system setting, here you can also ban all Internet connections globally. On request, it allows only selected programs to use the Internet and the tool is only suitable for experienced users.

Download link: https://download.cnet.com/TCPBlock/3000-10435_4-75326647.html
System software: macOS
File size: 1123 KB

Murus Lite

A type of firewall widely used on Mac computers. It has tools that are already integrated into the Apple operating system, where you can create different types of rules to manage images. It is characterized by the ease and advanced options that it presents in monitoring and that can be used in real-time.

Key Features

  • It has got an easy and intuitive icons-based and drag&drop-based interface.
  • Its PF firewall is quite a capable tool that helps to safeguard your Mac and network.
  • Full of advanced options and monitoring tools, this tool is perfect for everybody for a wide range of protection.
  • Use its graphical ruleset editor design tool or write fully customized rulesets using the advanced rule editor.
  • This wonderful tool is provided with full of advanced options and monitoring tools.

Highlights

There is no need to type a code or understand the PF syntax because an extended PF configuration view shows all the FP rules. It is a clear representation of the rules with icons and symbols with dynamically generated comments for each rule.

Download link: https://www.murusfirewall.com/
System software:
File size: 40.8 MB

Netiquette

The Netiquette refers to the appropriate language and format on the different platforms, good manners, the relevance of the content, respect for other opinions and privacy, among others, which are grouped as a code of conduct on the net.

Key Features

  • Respecting people’s time. Avoid messages at inappropriate times in media such as WhatsApp as this can cause discomfort.
  • Avoid the use of spams or content that cannot be desired by the person who will receive the email.
  • It is uncomfortable for many users to receive amounts of spam messages, and even more so if they are chains in which they ask to send 10 more friends.
  • Just as there are certain behaviors at parties, work meetings, circles of friends or classes at the university, the same happens in blogs, chats, social networks, discussion forums, and others.
  • Share your knowledge with other people, this makes cyberspace a means to teach and learn.
  • Keep debates and controversies under control, in a healthy and educational environment.

Highlights

Netiquette, as it is known in the virtual world, are simply the rules of etiquette in cyberspace. In other words, they are a set of rules for good online behavior.

NetLimiter

NetLimiter resembles a well and able firewall, as it monitors every connection on our computer, but it does not do so for security reasons, but rather to give us control over the consumption of bandwidth in each application.

Key Features

  • It is a lightweight application with advanced and powerful tools and modules.
  • It has a comfortable installation and one of its features is an easy to use graphical interface.
  • Includes remote administration, user administration, user permissions, and a firewall.
  • In addition to delimiting the Internet speed of applications, this tool will accept us to delimit the global speed.
  • Provides data reports in charts and tables that help organize regular monitoring. Users can adjust transit times to access a limited amount of traffic.
  • You can block network connectivity on individual programs or even restrict how much bandwidth a particular app gets.
Block outgoing connections

Highlights

Users can configure the limited download and upload speed for programs. The entire Internet network is in your hands, control preferences, set filters and also customize them for greater stability and performance.

Download link: https://www.netlimiter.com/
System software: Windows
File size: 7.9 MB

RadioSilence

This wonderful tool is one of the best network monitor and firewall for Mac. It can prevent any application from making network connections. It provides powerful privacy for your Mac. It is also possible to block unwanted traffic with the application-level firewalls.

Key Features

Block outgoing connections mac little snitch
  • It allows you to maintain a list of applications that cannot connect. Protect your privacy.
  • This tool prevents apps from calling home and you can save on bandwidth and data charges.
  • Though the firewall remains invisible it is always active. You don’t have to keep any windows open.
  • There are no annoying pop-ups. There is no clutter on your screen or base. No effect on the performance of your Mac.
  • Able to monitor normally inconspicuous activities allows you to make informed decisions regarding the transfer of your private information.

Highlights

This tool’s network monitor provides you a display about the network connection in real-time. And, in this process, if you can figure out an app, which is misbehaving, you have every freedom to block it with a single click.

Download link: https://radiosilenceapp.com/
System software:
File size: 2.7 MB

Vallum

This tool helps you monitor application connections. It is capable of intercepting application connections and maintaining them while you decide whether to pass or block them. The interface of this application is very simple and based on icons.

Key Features

  • To alter its attitude and level of interaction, you just have to play with the few options available.
  • This tool work at both application- and network-level to gain full control of your Mac
  • Configuration strategies allow you to choose from a list of predefined firewall configurations and attitudes.
  • This tool is not intrusive, it runs as a menu, let in the macOS menu bar, near the clock.
  • You don’t need to connect a home to verify your license, you don’t need any online activation.
  • It respects your privacy, it does not phone home or leaks any kind of data on the network.

Highlights

It is default setting is non-intrusive, it does not require any interaction or specific networking knowledge or skills. Just drag an app icon from the Finder to the main Vallum window to lock it.

Download link: http://www.vallum.in/
System software: macOS
File size: 31.9 MB

Apart from the above listed similar software to Little Snitch, you may consider ZoneAlarm which is a free firewall software that works with Windows 10 and older versions.

Why this post?

Hmm… Every SysAdmin, who love to play with Linux iptables must know, how iptables deal networking for a single user. You need to dig more on Linux iptables to get this option. Yeah, it’s possible!! Linux iptables has a special module to deal with this operation. This iptables module is called “owner” (ipt_owner).

Before starting, you must have the basics of iptables.. Please read the post added below to get a clear intro on Linux iptables:

What is iptables in Linux?

We can call, it’s the basics of Firewall for Linux. Iptables is a rule based firewall system and it is normally pre-installed on a Unix operating system which is controlling the incoming and outgoing packets. By-default the iptables is running without any rules, we can create, add, edit rules into it. Read More……

The module owner

This iptables module will attempt to match various characteristics of the packet creator, for locally generated packets. Not the point, it can only manage outgoing network access for a single user.

If someone ask you about “How you block all connections to a port for a process running under a user on the server?” or “How to block all incoming connections for a particular user?” by using iptables, you can answer “It Won’t Possible.” (Using, the by-default ipt_owner module)

This option is valid in the OUTPUT and POSTROUTING chains.

See the dmesg warning when I try to add it on INPUT chain 🙂

How To Block Outgoing Network Access For a Single User Using Iptables?

This option in iptables is very useful, if you want to block outgoing network activities for a particular user account on your Linux server/system. Here you can use owner module to match user and block all outgoing traffic for that user.

Scenario 1:

Consider this scenario, if you want to block all outgoing connections from a user “crybit” on the server, we can simply create an OUTPUT chain rule to do so.

See the rules and examples pasted below:

Syntax

I am guessing you are familiar with the commonly using iptables switches. Here, we have to use the following switches to define owner details.

-m owner : To define owner with the help of –uid-owner
–uid-owner {user name} : Matches if the packet was created by a process with the given effective username.

Block Outgoing Connections

You can use any jump (j) option like, DROP, REJECT etc as you wish…

Block Outgoing Connections Mac

It also support the following switches:

Example:

Test user is “crybit

Checking the user has network activities..

Yup, everything is okay!!

Now we are going to block outgoing network access for the user “crybit

Checking active ethernet link

You can use eth0 here.

Try again, now you can’t ping or dig as the user “crybit.”

That’s it!!

Block Outgoing Connections Mac Little Snitch

Block Outgoing Connections With Little Snitchodrenew

Scenario 2:

You can also block out going network activity for system defined users. Consider this scenario, if you want to block all outgoing network connections for Apache user. This can block someone downloading code into your server using wget or any other tools.

Check the user name for Apache server and add it to the rule using “-m owner –uid-owner” switch.

Don’t forget to allow email ports, 25,143,110 so that emails can work properly.

Create a new chain to deal this task.

Use new chain to process packets generated by apache user.

Define email ports to allow connections:

Reject everything else and stop the network activity for the user Apache:

Try it and let me know if you have any suggestions.