> For the complete documentation index, see [llms.txt](https://ajmal-anwar.gitbook.io/zyberspace-by-ajmal/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ajmal-anwar.gitbook.io/zyberspace-by-ajmal/zyberlab/06-network-security-basics/connectivity-testing.md).

# Connectivity Testing

This lab introduces simple ways to confirm whether ZyberLab systems can communicate.

## Objective

Test connectivity between `DC01`, `CLIENT01`, and `KALI01` and understand what a successful or failed test actually means.

## Test the Default Gateway

On each system, identify the default gateway and test it.

Windows:

```
ping <default-gateway>
```

Kali Linux:

```
ping -c 4 <default-gateway>
```

## Test Between Lab Systems

From `KALI01`, test `CLIENT01` and `DC01`.

```
ping -c 4 <CLIENT01-IP>
ping -c 4 <DC01-IP>
```

From `CLIENT01`, test `DC01`.

```
ping <DC01-IP>
```

## Understand a Failed Ping

A failed ping does not prove that a system is offline.

Possible reasons include:

* The target system is powered off
* The IP address is incorrect
* The systems are on different networks
* A firewall blocks ICMP echo traffic
* The network adapter is disconnected

Check the basics before changing firewall settings.

## Use Another Test

If ping is blocked, you can still test a known service later with tools such as `nslookup`, a browser, or a TCP connection test.

## Verification

The lab is complete when you can explain which systems can communicate and identify at least two reasons why ping might fail.

## Security Relevance

Connectivity testing helps separate network problems from application, DNS, firewall, and authentication problems. This is useful during both troubleshooting and security investigations.