An internet port is an additional piece of information that helps identify a process or service. For example, web browsing is associated with port number 80. The Internet Assigned Numbers Authority maintains the Service Name and Transport Protocol Port Number Registry and defines legitimate service names and port numbers.

Charter Communications takes the necessary steps to protect the privacy and security of its network and its customers by blocking internet ports that malicious software, vulnerabilities, and exploits use. Below is a list of ports that Charter blocks and why.

 

Port Name Description Justification
0   Reserved This port is reserved. No genuine internet traffic will use this port. Common exploits and vulnerabilities leverage this port.
17 qotd Quote of the Day This port is routinely exploited for Distributed Denial of Service attacks.
19 chargen Character Generator This port is routinely exploited for Distributed Denial of Service attacks.
135 epmap DCE endpoint resolution Microsoft has determined that permitting ports 135-139 allows NetBIOS and the Remote Procedure Call to be exploited. The vulnerabilities affect most currently supported Microsoft operating systems.
136 profile PROFILE Naming System
137 netbios-ns NETBIOS Name Service
138 netbios-dgm NETBIOS Datagram Service
139 netbios-ssn NETBIOS Session Service
445 Microsoft-ds Microsoft-DS Microsoft has determined that permitting port 445 NetBIOS to be exploited. The vulnerabilities affect most currently supported Microsoft operating systems.
520 router Routing information protocol: RIP This port is routinely exploited for Distributed Denial of Service attacks.
593 http-rpc-epmap HTTP RPC Ep Map Microsoft has determined that permitting port 593 Remote Procedure Call to be exploited. The vulnerabilities affect most currently supported Microsoft operating systems.
1433 ms-sql-s Microsoft-SQL-Server Microsoft and CERT.org determined that external access Microsoft SQL Servers enables several exploits and vulnerabilities.
1434 ms-sql-m Microsoft-SQL-Monitor
1900 ssdp SSDP This port is routinely exploited for Distributed Denial of Service attacks.
64623   Dynamic and/or Private Some customer premise equipment may be vulnerable to compromise on this port.
64680   Dynamic and/or Private Some customer premise equipment may be vulnerable to compromise on this port.