How to check network connectivity?

You can check network connectivity using several methods. Here are some common commands:

Ping Command: The ping command is used to test the reachability of a host on a network. For example, to check connectivity to a specific IP address or hostname:
```
ping <hostname_or_IP>
```
Example:
```
ping 8.8.8.8
```
Traceroute Command: The traceroute command shows the path packets take to reach a destination. It can help identify where connectivity issues occur:
```
traceroute <hostname_or_IP>
```
Example:
```
traceroute google.com
```
Netstat Command: The netstat command displays network connections, routing tables, and interface statistics. You can use it to check active connections:
```
netstat -tuln
```
Curl Command: The curl command can be used to check if a specific service is reachable. For example, to check if a web server is responding:
```
curl -I http://<hostname_or_IP>
```
Example:
```
curl -I http://example.com
```
Ifconfig or Ip Command: Use ifconfig or ip to check your local network interfaces and their statuses:
```
ifconfig
```
or
```
ip addr
```
Network Diagnostic Tools: Tools like nmap can be used to scan for open ports and services on a network:
```
nmap <hostname_or_IP>
```

By using these commands, you can effectively diagnose and troubleshoot network connectivity issues.