Is port 23 (Telnet) dangerous?

Port 23 is classified as critical risk and should not be exposed to the public internet. It transmits data without encryption, making it vulnerable to eavesdropping and credential theft.

Should port 23 be open on my firewall?

No, port 23 should not be open to the public internet. Block it at the firewall and use encrypted alternatives such as SSH, SFTP, or HTTPS instead.

What transport protocol does port 23 use?

Port 23 (Telnet) uses the TCP transport protocol and falls under the Remote Access category.

:23 (TCP)

Telnet

Critical 风险

TCP — Remote Access

端口概览

端口号 23

服务名称 Telnet

传输协议 TCP

类别 Remote Access

安全风险 Critical

端口范围知名端口 (0-1023)

什么是端口 23?

Telnet protocol. Provides unencrypted text-based remote login to network devices and servers. All data including passwords is sent in plaintext.

TCP Remote Access 常用

安全注意事项

端口23（Telnet）被归类为严重风险。此端口不应暴露在公网上。该服务在未加密的情况下传输数据，容易受到窃听、凭据窃取和中间人攻击。

建议：在防火墙处封锁此端口。改用加密替代方案（SSH、SFTP、HTTPS）。

Telnet

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端口概览

什么是端口 23?

安全注意事项

相关协议

相关端口 — Remote Access

相关术语