What is port 135? Detailed explanation of the principle and function of port 135

in the communication system of computer networks, ports are the key entry points for data transmission between devices, and different ports undertake specific network service functions. Port 135, as a well-known port in the TCP/IP protocol stack, plays a core role in the network architecture of Windows systems, but is often ignored by ordinary users. This article will analyze the core value and application points of port 135 from technical principles, practical functions to security protection, and help readers establish a comprehensive understanding of this key port and master the method of rationally configuring port 135.

What is the core definition of port 135?

to understand the role of port 135, it is first necessary to clarify its basic definition and positioning, which is the core premise of mastering its function.

1, 135 port basic properties

135 port is a well-known port shared by TCP and UDP protocols, which is mainly related to remote procedure call services in Windows systems, which is often referred to as RPC services. In network communication, the core role of port 135 is as the registration and query entry of RPC services, responsible for receiving client service requests and forwarding them to the corresponding back-end server level port. It is a key hub for distributed application communication in Windows systems.

Applicable scenarios for

2 and 135 ports

135 port is mainly used in the Windows system environment and plays a role in scenarios such as domain management, remote desktop connection, and system service invocation. Whether it is server management in the enterprise intranet or remote assistance operation for individual users, port 135 is the basic entrance to realize cross-device service communication. Without the support of port 135, the remote management function of most Windows systems will not operate normally.

What is the working principle of port 135?

understand the operation logic of port 135, can help readers more clearly understand its flow path in network communication, understand its core value.

1, 135 port service registration mechanism

Windows system start-up, all RPC-dependent services will register their service identifiers and listening ports with port 135. Port 135 will maintain a service mapping table to record the port information corresponding to each service. When the client side initiates a service request, it will first query port 135 for the actual port of the target service, and then establish direct communication with the service through this port. Port 135 plays the role of "service intermediary" in this process.

2, 135 port request forwarding process

when the client side needs to invoke a remote service, it will first send a query request to port 135 of the target device, carrying the identification information of the target service. After port 135 receives the request, it will find the corresponding port number in the internal service mapping table, and then return the port information to the client side. After the client side obtains the port number, it directly establishes a connection with the port to complete the subsequent data transmission. In the whole process, port 135 is only responsible for port query and does not participate in the actual data interaction.

What are the practical functions of port 135?

as the core communication port of the Windows system, the role of port 135 runs through multiple scenarios of system management and service invocation, and is the key support to ensure the distributed function of the system.

1, 135 ports and system remote management

135 port is the basic support port of Windows remote desktop service and remote server management tool. When administrators use remote desktop connection and MMC console to manage remote servers, they first need to query the actual port of remote services through port 135 to establish a stable management connection. Without the support of port 135, the remote management function of cross-device system will not be realized, which is also the core reason why port 135 is valued in enterprise IT operation and maintenance.

2, 135 ports communicate with distributed services

in the Windows domain environment, port 135 acts as a service communication intermediary between the domain controller and the client side. When the client side needs to access the user authentication service and file sharing service in the domain, it will first query the server level port through port 135, and then complete the subsequent service invocation. The existence of port 135 makes the port management of distributed services more flexible, and the service can dynamically adjust the port without affecting the access logic of the client.

Security risks and protection of port 135?

due to the core position of port 135, it has also become a key target of network attacks, it is essential to master the security protection method of port 135.

Common security risks for

1 and 135 ports

The main security risk of the

135 port comes from the vulnerability exploitation of the RPC service. An attacker can scan the open port 135 and send a malicious request to trigger the vulnerability of the RPC service, and then obtain system permissions or initiate Distributed Denial-of-service. In addition, the open port 135 may also disclose the server level port information of the system, which provides convenience for subsequent port scanning and attacks. Therefore, the unprotected port 135 will become a security risk to the system.

2, 135 port security protection method

for the security protection of port 135, first of all, the access range of port 135 can be restricted through the firewall, and only the trusted Internet Protocol Address can access port 135 to avoid malicious scanning from the public network. Secondly, timely update the system patch to fix the known vulnerabilities of the RPC service and block the attacker's exploit path. For devices that do not need remote management, you can also directly disable the RPC service and close port 135 to eliminate security risks from the root cause.

To sum up, port 135 is the core intermediary port of Windows system network communication, which plays a key role in service registration, query and request forwarding, and is the basic support for remote management and distributed service communication. At the same time, the openness of port 135 also brings certain security risks, which need to be protected by firewall configuration and patch update. Reasonable cognition and configuration of port 135 can not only ensure the normal operation of system functions, but also effectively improve the security of the network environment.