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Blocked internet ports on the Virgin Media network

In order to protect our customers and our network, a number of ports on the Virgin Media network are blocked.

Ports on the Internet are like virtual doors that data can pass through. All internet traffic passes through ports to get to and from systems and services across the Internet.

When a certain port is known to be subject to security vulnerabilities, we sometimes block that port on our network.

These ports are blocked at network-level. Traffic over these ports within your home network will continue to operate as normal, but will be inaccessible to devices outside your network.

Blocked ports

TCP & UDP ports 135, 137, 138, 139 – Used by the NetBIOS service

NetBIOS services allow file sharing over a local network. When exposed to the Internet, it can be exploited to carry out malicious activities such as Distributed Denial of Service (DDoS) attacks or to gain unauthorised access to systems on a local network.

TCP & UDP port 445 – Used by the SMB protocol

Port 445 is vulnerable to a number of attacks which target vulnerabilities in systems running file-sharing services. This port is used by various malware strains to gain entry to a network, namely the WannaCry and Nimda malware variants.

You can find further advice regarding security issues including what to do if you’ve been the victim of online fraud or cybercrime from our Security Hub.

* Links to external sites are provided as a courtesy and we are not responsible for the content of these sites or any problems encountered whilst applying these steps and we are not able to provide any technical support for such problems.

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