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.
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.
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