Unusual Network Port Activity Businessman using computer laptop with triangle caution warning sign

If you’re experiencing unusual network port activity, it’s a sign that your device is infected with a virus or malware or involved in a security breach.

Unknown devices on your network could be causing unusual activity in your network traffic. This allows cybercriminals to install malware on your device, steal your private information and banking details and lead to online identity theft.

It’s dangerous to leave any unusual network port problems unresolved. If you receive a notification from Google stating, “Our systems have detected unusual traffic from your computer network,” it’s time to take action.

Fortunately, there are many ways to fix unusual network port activity, and a lot of it can be done quickly using antivirus software.

This guide will explain how to fix unusual network port activity using a few simple steps.

Unusual network port activity: Quick fixes

To help identify and resolve unusual network port activity, follow the steps below in order. If one fix doesn’t work, try the next step until you find the right solution.

  1. Identify and block unusual network activity

    Windows Defender Firewall Settings

    It can be hard to figure out where the unusual network port activity is coming from. However, if you monitor your network traffic for any suspicious activity that isn’t your own, you can identify and block the traffic from the source. 

    Using a network security monitoring (NSM) or intrusion detection system (IDS) tool can help you determine what’s causing the issue. Using tools such as PRTG Network Monitor for small networks or SolarWinds Network Performance Monitor (free trial available) for more extensive networks can identify where the malware infection or security threat is coming from. 

    Once the issue has been found, block the suspicious network traffic at its source by turning on or configuring a firewall.

    Depending on your system, you can turn on the device’s firewall through its settings. For example, you can turn on Windows Defender Firewall by heading to Start > Control Panel > System and Security > Windows Defender Firewall > Turn Windows Firewall on or off > Turn on Windows Firewall

    If you’re using antivirus software, it may already be managing your firewall settings. 

  2. Change your passwords

    Norton 360 Password Manager

    If you’ve already noticed unusual network port activity, chances are your online accounts and devices have been compromised. To help mitigate potential malware threats or hackers taking control of your accounts, change your passwords and use a strong password to stop suspicious activity. 

    Using password managers such as LastPass or 1Password can help manage all your passwords in one place, create a complex, near-unbreakable master password and encrypt your information. 

    Changing passwords will stop hackers from trying to steal any sensitive information and your online accounts. 

  3. Update your software

    Windows PC Update Settings

    Cybercriminals take advantage of security vulnerabilities on your device. These zero-day vulnerabilities allow threat actors to exploit computer systems until developers mitigate them, which can cause a lot of damage. 

    Updating your system’s software can resolve the issue. A software update often contains security patches that help protect your network, as developers work to protect users from known zero-day attacks and other forms of malware trying to infect your device. 

    You can update your device through its settings. For example, you can update your Windows PC by navigating to Start > Settings > Windows Update > Check for updates. If there are any, download and install the update. 

  4. Use antivirus software to detect and stop malware

    Norton 360 Security and Settings

    If you can’t find any way to solve unusual network port activity, using one of the best antivirus software like Norton 360 (from $19.99/year) will keep you safe from any malicious software, like ransomware, adware, spyware, phishing and more.

    That’s not all; antivirus software can provide extra features like VPNs, cloud storage, PC boosters, and more. Norton 360 has all these features and extra security tools that can backup your data, prevent online identity theft and stop malware. 

    What’s more, Norton 360 comes with a Network Monitoring Filter feature to monitor all the network activities and block malicious websites. It will help detect and notify you about any unusual network activity and stop it using its firewall. 

    Check out our Norton 360 review and Norton 360 Platinum review to see which antivirus package suits you best. 

What is a network port?

A network port is a software construct in computer networking that identifies a specific process or type of network service. It is a software-specific number, also called a port number, that identifies a connection endpoint and directs data to a specific service.

Every network and device uses a specific network port to transmit and receive data, as it is used to communicate with services and devices. Common transport protocols using port numbers include the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). For example, a port number is associated with the network address of a host, such as an IP address.

There are different types of port numbers. This includes well-known ports used by known network services you’ll see in web page links like HTTP (port 80) and HTTPS (port 443); registered ports used by registered network services like SMTP (port 25) and DNS (port 53); and private port, used by various applications that don’t have well-defined port numbers, including gaming applications and file sharing applications.

For a better understanding, here are some examples of network ports and what they do:

  • HTTPS (Hypertext Transfer Protocol Secure) – a secure version of HTTP and used for transmitting web pages.
  •  DNS (Dome Name System) – used for translating domain names into IP addresses.
  •  SMTP (Simple Mail Transfer Protocol) – used for sending emails
  •  FTP (File Transfer Protocol) – used for transferring files between devices.

Well-known and registered ports are constantly under watch and are safe network protocols, but others that aren’t as well-known are the

What can cause unusual network port activity?

There are many issues that can cause unusual network port activity. Generally, it’s a warning that suspicious port connections are not being used for legitimate purposes or connections to ports and are being used by malware.

Common causes include the following:

  • Malware – malicious software can use unfamiliar ports to send and receive information with a threat actor’s command and control (C&C) server
  •  Botnets – botnets are networks of infected computers often controlled by attackers. These can use unusual network ports to stay undetected.
  •  Denial-of-service (DoS) attacks – a DoS cyberattack can make your device unusable by overwhelming the device with requests until traffic can’t be processed. This will also use unusual ports to overwhelm a network.
  •  Network misconfiguration – if a firewall or router is misconfigured to allow suspicious network traffic to come through, it can cause unusual activity.

While all of these causes can be threatening, they can be quickly resolved using antivirus software like Norton 360 (from $19.99/year).

Norton 360 Platinum on Laptop

How can I prevent unusual network port activity?

Keeping your network safe from unusual activity is easier than it sounds. By having the right security tools on your device to detect and block malicious software, you can keep your network free of threat actors trying to nab your private information.

There are a few ways to prevent unusual network port activity. This includes keeping your software up to date, as they have security patches to help protect your network from malware.

Using a firewall can block unauthorised traffic from entering your network, and network monitoring software like an IDS can detect suspicious activity.

You should also use a strong password and change it regularly to stop hackers from breaking into your accounts. Password managers make it easy to stay on top of this.

It’s a good idea to stay clear of any suspicious links in emails and dodgy websites. These phishing attacks are designed to install malware on your device. You can learn more about the most common types of phishing attacks and how to stay safe from there with our guide.

The most effective way to prevent unusual network port activity is to use one of the best antivirus software. They can let you do all these methods with a simple click of a button and come with enhanced security features such as firewalls and network monitoring – just like Norton 360.

Can any antivirus software stop unusual network port activity?

The best antivirus software will stop malware in its tracks. Not all antivirus software is equal, as some don’t have high malware detection and protection rates or have accredited lab scores to back them up.

However, many high-standard AV protections offer near-perfect scores when detecting and protecting against malware, meaning even complex malicious software can’t go unnoticed.

Services, including Norton 360 (from $19.99/year) and Bitdefender (from $19.99/year), include network monitoring features to help uncover suspicious activity early and offer the tools to fight off cyberattacks.

These services have protection tools that block malicious network port activity, links and attachments. To make sure your device is ready to identify and block malware damaging your system, set yourself up with an antivirus.

Best antivirus to detect and prevent unusual network port activity

1. Norton 360 🥇From $19.99/year
Best overall antivirus of 2023

Norton 360 on Laptop scaled

“Norton” and “antivirus” are synonymous these days, as the well-established cybersecurity brand has successfully fought against malware, viruses and nasty software threats since 1990. 

Norton 360 offers excellent antivirus protection and extra features that make for a valuable, all-in-one security product. Its Norton 360 Deluxe and Premium package may cost a pretty penny. Still, with security across multiple platforms, a full-blown VPN, Dark Web Monitoring, Parental Controls and more, it will have a household free of cyber threats. 

Norton’s certainty of its antivirus software’s capabilities is clearly defined by the brand’s 100% Virus Protection Promise. If a device protected by Norton 360 can’t get rid of a virus, the user receives their money back. It’s a big claim, but unquestionably, no one should expect to get that refund.

If you have the money for it, you can also check out the premium Norton 360 Platinum package for even more online protection, including from identity theft. Without a doubt one of the best antivirus to get.

Read our full Norton 360 review

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2. Bitdefender 🥈 From $19.99/year
Best security features and tools

Bitdefender Lead Image scaled

Bitdefender takes the spot as best antivirus, and for good reason. It’s not enough that it boasts near-perfect lab test scores across the board, as it goes the extra mile by giving users access to a plethora of advanced security features.

Bitdefender goes above and beyond in the features department, all while keeping known malware, ransomware, and viruses at bay. It will defend your device against new attacks, provide security for online transactions, keep you safe with a reliable VPN, and protect your accounts with a password manager.

It’s a no-brainer when it comes to defending your devices against virtually any form of cyberattack, and its top-notch protection extends to its most affordable package, too. Protecting your PC and smartphone, from Windows and macOS to iOS and Android, is becoming even more necessary, and Bitdefender is the tricked-out shield you need. 

Read our full Bitdefender review

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3. Malwarebytes 🥉 From $44.99/year
Best antivirus for Windows PC

Malwarebytes Logo scaled

Hundreds of malware emerge every minute, and it’s Malwarebytes’ mission to detect and conquer them all. Does the antivirus do this successfully? Yes, but there’s wiggle room for improvements.

Malwarebytes’ no-nonsense approach to protecting your devices from the onslaught of malware and viruses is effective for those who need a reliable antivirus that will detect and remove malicious software, especially with its free version. However, while its premium service provides 24/7 real-time detection, conveniently blocks vicious ransomware and shields users from malicious websites, it doesn’t go beyond on the feature front.

That’s no bad thing, as sometimes a user only needs a powerful antivirus to keep them safe from cyber threats. But considering its competitors add a few more security tools, such as data breach monitoring and a firewall, there’s room for improvement. 

Read our full Malwarebytes review

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4. Avast One 🙌 From $39.99/year
Best antivirus for beginners + free plan available!

Avast One logo on laptop

With Avast One, you can protect your device from viruses, malware and ransomware for free. That’s right, and you don’t have to pay a dime for the extra security features the antivirus throws in, including its VPN, firewall and more.

Avast One will safeguard your device from malware, comes with ransomware protection, blocks harmful websites and downloads from the web, scans your emails for malicious attachments, stops hackers from infiltrating your device through Wi-Fi with a firewall – the list goes on. That’s a lot of tools for software that’s free, and the included VPN and the ability to speed up your PC are a welcome bonus.

It’s the ideal antivirus software for home use, as it takes the hassle out of staying wary of cyber threats lurking around, even if you’re not a tech whizz. What’s more, if you are looking for added precautions, its paid Individual and Family packages still boast great value. Hard to go wrong with this best antivirus.

Read our full Avast One review

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5. AVG👍 From 4.99/month
Best antivirus for + free plan available!

AVG Antivirus logo scaled

You can never go wrong with free antivirus protection, but some deliver even better detection and protection rates, along with extra security features, without costing a dime. This is where AVG antivirus shines.

AVG provides reliable protection and only a small impact on performance for Windows, Mac, iOS and Android. It safeguards your devices against malware, viruses and zero-day exploits, along with blocking malicious links and attachments in emails. Throw in phishing protection when surfing the internet and extra security features such as its SafePrice browser extension and Network Inspector, and you’ve got yourself a do-it-all antivirus.

Sure, you can find all of these perks with Avast, but if you like a slick, darker user interface that’s easy to navigate, then AVG is for you.

Read our full AVG Antivirus review

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Darragh Murphy
Darragh Murphy is fascinated by all things bizarre, which usually leads to assorted coverage varying from the mischievous world of online security to washing machines designed for earbuds. Whether it's connecting Scar from The Lion King to two-factor authentication or turning his love for laptops into a fabricated rap battle from 8 Mile, he believes there’s always a quirky spin to be made. When he's not checking out the latest devices and all things tech, he can be found swimming laps, watching terrible shark movies, and trying to find time to game.  Previous Editor at Laptop Mag and News Editor at Time Out Dubai, specialising in food culture, nightlife events, gaming, tech and entertainment.


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