What tools do you use for diagnosing and testing TCP connections?

For diagnosing and testing TCP connections in Go, the following tools and methods are often used:

• net.Dial and net.Listen — standard functions for establishing and listening to TCP connections, allowing to check basic functionality.
• tcpdump or Wireshark — external tools for analyzing network traffic, helping to see packets and understand what happens at the protocol level.
• telnet or nc (netcat) — for simple testing of TCP ports and connections.
• Go profilers and logging — for debugging and monitoring the operation of TCP servers and clients.

Example of a simple TCP client in Go:

package main

import (
    "fmt"
    "net"
    "time"
)

func main() {
    conn, err := net.DialTimeout("tcp", "example.com:80", 5*time.Second)
    if err != nil {
        fmt.Println("Connection error:", err)
        return
    }
    defer conn.Close()
    fmt.Println("Connection established")
}