端口检测器
检测某个TCP端口是否开放并接受来自互联网的连接。
如何使用本工具
- 1
Type the public hostname or IP you want to probe (for example example.com) into the host field.
- 2
Set the port number, either by typing it or clicking one of the quick presets like 22, 80, 443, or 3306.
- 3
Click Check and wait up to five seconds for the result.
- 4
Read the result banner: green means the port accepted a TCP connection (with latency in milliseconds), red means it did not (with the reason code).
什么是端口检测器？
网络服务在TCP端口上监听：Web服务器在80/443，SSH在22，数据库在3306/5432。如果某个端口被关闭或受防火墙保护，则任何连接都无法成功。本工具会尝试从我们的服务器向你指定端口上的主机打开一个TCP套接字：这对于调试防火墙规则、验证服务是否确实对外暴露或审计安全性很有用。
常见使用场景
Confirm a freshly deployed web app is reachable on port 443 before pointing DNS or a load balancer at it.
Diagnose why clients cannot connect to a database by checking whether 3306 or 5432 is actually exposed.
Verify a new firewall or security-group rule opened (or closed) the port you intended.
Check that a sensitive service like Redis on 6379 or MongoDB on 27017 is NOT left open to the public internet.
Test whether an outbound SSH or SMTP port is blocked between a remote host and the public internet.
Validate that a port-forward or reverse proxy is passing traffic through to the expected backend port.