# VPC Flow Logs - Analyzing Network Traffic - GSP212

## Setup and requirements

### Before you click the Start Lab button

Read these instructions. Labs are timed and you cannot pause them. The timer, which starts when you click **Start Lab**, shows how long Google Cloud resources are made available to you.

This hands-on lab lets you do the lab activities in a real cloud environment, not in a simulation or demo environment. It does so by giving you new, temporary credentials you use to sign in and access Google Cloud for the duration of the lab.

To complete this lab, you need:

*   Access to a standard internet browser (Chrome browser recommended).
    

**Note:** Use an Incognito (recommended) or private browser window to run this lab. This prevents conflicts between your personal account and the student account, which may cause extra charges incurred to your personal account.

*   Time to complete the lab—remember, once you start, you cannot pause a lab.
    

**Note:** Use only the student account for this lab. If you use a different Google Cloud account, you may incur charges to that account.

### How to start your lab and sign in to the Google Cloud console

1.  Click the **Start Lab** button. If you need to pay for the lab, a dialog opens for you to select your payment method. On the left is the Lab Details pane with the following:
    
    *   The Open Google Cloud console button
        
    *   Time remaining
        
    *   The temporary credentials that you must use for this lab
        
    *   Other information, if needed, to step through this lab
        
2.  Click **Open Google Cloud console** (or right-click and select **Open Link in Incognito Window** if you are running the Chrome browser).
    
    The lab spins up resources, and then opens another tab that shows the Sign in page.
    
    ***Tip:*** Arrange the tabs in separate windows, side-by-side.
    
    **Note:** If you see the **Choose an account** dialog, click **Use Another Account**.
    
3.  If necessary, copy the **Username** below and paste it into the **Sign in** dialog.
    
    ```apache
    student-04-f2d0d960d710@qwiklabs.net
    ```
    
    You can also find the Username in the Lab Details pane.
    
4.  Click **Next**.
    
5.  Copy the **Password** below and paste it into the **Welcome** dialog.
    
    ```apache
    toh5EZslzcgg
    ```
    
    You can also find the Password in the Lab Details pane.
    
6.  Click **Next**.
    
    **Important:** You must use the credentials the lab provides you. Do not use your Google Cloud account credentials.
    
    **Note:** Using your own Google Cloud account for this lab may incur extra charges.
    
7.  Click through the subsequent pages:
    
    *   Accept the terms and conditions.
        
    *   Do not add recovery options or two-factor authentication (because this is a temporary account).
        
    *   Do not sign up for free trials.
        

After a few moments, the Google Cloud console opens in this tab.

**Note:** To access Google Cloud products and services, click the **Navigation menu** or type the service or product name in the **Search** field.

![Navigation menu icon and Search field](https://cdn.qwiklabs.com/9Fk8NYFp3quE9mF%2FilWF6%2FlXY9OUBi3UWtb2Ne4uXNU%3D align="left")

### Activate Cloud Shell

Cloud Shell is a virtual machine that is loaded with development tools. It offers a persistent 5GB home directory and runs on the Google Cloud. Cloud Shell provides command-line access to your Google Cloud resources.

1.  Click **Activate Cloud Shell** at the top of the Google Cloud console.
    
2.  Click through the following windows:
    
    *   Continue through the Cloud Shell information window.
        
    *   Authorize Cloud Shell to use your credentials to make Google Cloud API calls.
        

When you are connected, you are already authenticated, and the project is set to your **Project\_ID**, `qwiklabs-gcp-00-a05900279721`. The output contains a line that declares the **Project\_ID** for this session:

```apache
Your Cloud Platform project in this session is set to qwiklabs-gcp-00-a05900279721
```

`gcloud` is the command-line tool for Google Cloud. It comes pre-installed on Cloud Shell and supports tab-completion.

3.  (Optional) You can list the active account name with this command:
    

```apache
gcloud auth list
```

4.  Click **Authorize**.
    

**Output:**

```apache
ACTIVE: *
ACCOUNT: student-04-f2d0d960d710@qwiklabs.net

To set the active account, run:
    $ gcloud config set account `ACCOUNT`
```

5.  (Optional) You can list the project ID with this command:
    

```apache
gcloud config list project
```

**Output:**

```apache
[core]
project = qwiklabs-gcp-00-a05900279721
```

**Note:** For full documentation of `gcloud`, in Google Cloud, refer to [the gcloud CLI overview guide](https://cloud.google.com/sdk/gcloud).

## Task 1. Configure a custom network with VPC Flow Logs

### Create the custom network

By default, VPC Flow Logs are disabled for a network. Therefore, you will create a new custom-mode network and enable VPC Flow Logs.

1.  In the Console, navigate to **Navigation menu** () > **VPC network** > **VPC networks**.
    
    ![The navigation path to the VPC networks option](https://cdn.qwiklabs.com/kHFA7kqMeawU3GQ0qfj29u%2B1hGieMSEZWl6Su0S1Ry4%3D align="left")
    
2.  Click **Create VPC Network**.
    
3.  Set the following values, leave all others at their defaults:
    
    | **Property** | **Value (type value or select option as specified)** |
    | --- | --- |
    | Name | vpc-net |
    | Description | Enter an optional description |
    
4.  For **Subnet creation mode**, click **Custom**.
    
5.  Set the following values, leave all others at their defaults:
    
    | **Property** | **Value (type value or select option as specified)** |
    | --- | --- |
    | Name | vpc-subnet |
    | Region | `europe-west1` |
    | IPv4 range | 10.1.3.0/24 |
    | Flow Logs | On |
    
6.  Click **Done**, and then click **Create**.
    

**Note:** Turning on VPC flow logs doesn't affect performance, but some systems generate a large number of logs, which can increase costs.

**Note:** Wait for the network to be created before proceeding to the next step.

### Test Completed Task

Click **Check my progress** to verify your performed task. If you have completed the task successfully you will granted with an assessment score.

Create the custom network.

**Check my progress**

Create a subnet for the custom network in `europe-west1` region.

**Check my progress**

### Create the firewall rule

In order to serve HTTP and SSH traffic on the network, you need to create a firewall rule.

1.  In the left menu, click **Firewall**.
    
2.  Click **Create Firewall Rule**.
    
3.  Set the following values, leave all others at their defaults:
    
    | **Property** | **Value (type value or select option as specified)** |
    | --- | --- |
    | Name | allow-http-ssh |
    | Network | vpc-net |
    | Targets | Specified target tags |
    | Target tags | http-server |
    | Source filter | IPv4 ranges |
    | Source IPv4 ranges | 0.0.0.0/0 |
    | Protocols and ports | Specified protocols and ports, and then *check* tcp, *type:* 80, 22 |
    

**Note:** Make sure to include the **/0** in the **Source IPv4 ranges** to specify all networks.

4.  Click **Create**.
    

### Test completed task

Click **Check my progress** to verify your performed task. If you have completed the task successfully you will granted with an assessment score.

Create the firewall rule in the custom network.

**Check my progress**

## Task 2. Create an Apache web server

### Create the web server

1.  In the **Cloud console**, on the **Navigation menu** (☰), click **Compute Engine** > **VM Instances**, then click **Create instance**.
    
2.  In the **Machine configuration**
    
    Enter the values for the following fields:
    
    | **Field** | **Value** |
    | --- | --- |
    | **Name** | `web-server` |
    | **Region** | `europe-west1` |
    | **Zone** | `europe-west1-b` |
    | **Series** | `E2` |
    | **Machine Type** | `e2-micro (2 vCPU, 1GB memory)` |
    
3.  Click **Networking**
    
    *   **Firewall**: Allow HTTP traffic
        
    *   **Network interfaces** : click on `default` to edit.
        
        *   **Network**: `vpc-net`
            
        *   **Subnetwork**: `vpc-subnet`
            
4.  Once all sections are configured, scroll down and click **Create** to launch your new virtual machine instance.
    
    Wait a couple of minutes, you'll see a green check when the instance has launched.
    

### Test completed task

Click **Check my progress** to verify your performed task. If you have completed the task successfully you will granted with an assessment score.

Create the web server in the custom network (zone:`europe-west1-b`).

**Check my progress**

### **Install Apache**

Configure the VM instance that you created as an Apache webserver and overwrite the default web page.

1.  Return to the Console, still on the VM instances page (**Navigation menu** (
    
    ![Navigation menu icon](https://cdn.qwiklabs.com/tkgw1TDgj4Q%2BYKQUW4jUFd0O5OEKlUMBRYbhlCrF0WY%3D align="left")
    
    ) > **Compute Engine** > **VM instances**). For **web-server**, click **SSH** to launch a terminal and connect.
    
2.  In the **web-server** SSH terminal, update the package index:
    

```apache
sudo apt-get update
```

3.  Install the Apache2 package:
    

```apache
sudo apt-get install apache2 -y
```

4.  Create a new default web page by overwriting the default:
    

```apache
echo '<!doctype html><html><body><h1>Hello World!</h1></body></html>' | sudo tee /var/www/html/index.html
```

5.  Exit the SSH terminal:
    

```apache
exit
```

### Test completed task

Click **Check my progress** to verify your performed task. If you have completed the task successfully you will granted with an assessment score.

Install Apache in web server.

**Check my progress**

## Task 3. Verify that network traffic is logged

### Generate network traffic

1.  Return to the Console, still on the VM instances page (**Navigation menu** (
    
    ![Navigation menu icon](https://cdn.qwiklabs.com/tkgw1TDgj4Q%2BYKQUW4jUFd0O5OEKlUMBRYbhlCrF0WY%3D align="left")
    
    ) > **Compute Engine** > **VM instances**).
    
2.  To view **web-server**, click the **External IP** to access the server.
    

**Note:** The **Hello World!** welcome page, which you configured, opens. Alternatively, you can access the server in a new tab by navigating to http://*Enter the external IP Address*.

### **Find your IP address**

Find the IP address of the computer you are using. One easy way to do this is to go to a website that provides this address.

1.  Click [whatismyip.host](http://whatismyip.host/) to find your IP v4 address.
    
2.  Copy your IP address. It will be referred to as `YOUR_IP_ADDRESS`.
    

### Access the VPC Flow Logs

1.  In the Console, navigate to **Navigation menu** > **View All Products** > **Logging** > **Logs Explorer**.
    
2.  In the **Log fields** panel, under **Resource type**, click **Subnetwork**. In the Query results pane, entries from the subnetwork logs appear.
    
3.  In the **Log fields** panel, under **Log name**, click **compute.googleapis.com/vpc\_flows**.
    
4.  Enter `"YOUR_IP_ADDRESS"` in the Query search box at the top. Then Click **Run Query**.
    

**Note:** If you do not see the **compute.googleapis.com/vpc\_flows** filter option or no logs, you might have to wait a couple of minutes and refresh.

![The highlighted Run query button within the Logs Explorer page.](https://cdn.qwiklabs.com/9eM%2FSr0BcrBIlhKyqdI7zLdEkYywT4QkrjuFLCuAW4U%3D align="left")

5.  Click on one of the log entries to expand it.
    
6.  Within the entry, click the arrows to expand the **jsonPayload** and then the **connection**. You may have to click **Expand all** to see the **connection**.
    

![All connections listed in the Query results](https://cdn.qwiklabs.com/tFQEz45DmrXNIZeRv7MbU%2BiJNZOXCtpEiXNImU62ZOw%3D align="left")

**Note:** The **connection** contains the destination IP address/port number, the protocol, and the source IP address/port number. Depending on the direction of the traffic, the destination is either your web-server or the machine you are working on and vice-versa for the source.

The protocol should be **6**, which is the IANA protocol for TCP traffic. One of the port numbers will be **80**, representing HTTP port on the **web-server** and the other port number should be a number greater than **1024**, representing HTTP port on your machine.

Which fields does the connection contain?Source IP addressSource portDestination IP addressDestination portThe IANA protocol number

**Submit**

Feel free to explore other fields within the log entry before moving to the next task.

## Task 4. Export the network traffic to BigQuery to further analyze the logs

### Create an export sink

1.  In the Console, in the left pane, click **Logs Explorer**.
    
2.  From **Resources** dropdown, select **Subnetwork**. Then click **Apply**.
    
3.  From **Log name** dropdown, check **vpc\_flows** and click **Apply**. Then, click **Run query**.
    
4.  Click **More Actions > Create Sink**.
    
5.  For "Sink Name", type **vpc-flows** and click **NEXT**.
    
6.  For "Select sink service", select the **BigQuery dataset**.
    
7.  For "Sink Destination", select **Create new BigQuery dataset**.
    
8.  For "Dataset ID", type **bq\_vpc\_flows**, and then click **CREATE DATASET**.
    
9.  Click **CREATE SINK**. The Logs Router Sinks page appears. You should be able to see the sink you created (vpc-flows). If you are unable to see the sink click on **Logs Router**.
    

### Generate log traffic for BigQuery

Now that the network traffic logs are exported to BigQuery, generate more traffic by accessing the web-server several times. Using Cloud Shell, you can `curl` the IP Address of the web-server several times.

1.  In the Console, navigate to **Navigation menu** (
    
    ![Navigation menu icon](https://cdn.qwiklabs.com/tkgw1TDgj4Q%2BYKQUW4jUFd0O5OEKlUMBRYbhlCrF0WY%3D align="left")
    
    ) > **Compute Engine** > **VM instances**.
    
2.  Note the **External IP** address for the **web-server** instance to use in the next step. It will be referred to as `EXTERNAL_IP`.
    
3.  In the Cloud Shell command line, run the following command to store the `EXTERNAL_IP` in an environment variable. Replace the <EXTERNAL\_IP> with the address you just noted:
    

```apache
export MY_SERVER=<EXTERNAL_IP>
```

4.  Access the web-server 50 times from Cloud Shell:
    

```apache
for ((i=1;i<=50;i++)); do curl $MY_SERVER; done
```

### Test completed task

Click **Check my progress** to verify your performed task. If you have completed the task successfully you will granted with an assessment score.

Export the network traffic to BigQuery.

**Check my progress**

### Visualize the VPC Flow Logs in BigQuery

1.  In the Console, navigate to **Navigation menu** (
    
    ![Navigation menu icon](https://cdn.qwiklabs.com/tkgw1TDgj4Q%2BYKQUW4jUFd0O5OEKlUMBRYbhlCrF0WY%3D align="left")
    
    ) > **BigQuery**.
    
2.  Click **Done**.
    
3.  On the left-hand side, expand the **bq\_vpc\_flows** dataset to reveal the table. You might have to first expand the **Project ID** to reveal the dataset.
    
4.  Click on the name of the table. It should start with **compute\_googleapis**.
    

**Note:** If you do not see the **bq\_vpc\_flows** dataset or it does not expand, wait and refresh the page.

5.  Click on **Details** tab.
    
6.  Copy the **Table ID** provided in the `Details` tab.
    
7.  Add the following to the Query Editor and replace **your\_table\_id** with `TABLE_ID` while leaving the accents (\`) on both sides:
    

```apache
#standardSQL
SELECT
jsonPayload.src_vpc.vpc_name,
SUM(CAST(jsonPayload.bytes_sent AS INT64)) AS bytes,
jsonPayload.src_vpc.subnetwork_name,
jsonPayload.connection.src_ip,
jsonPayload.connection.src_port,
jsonPayload.connection.dest_ip,
jsonPayload.connection.dest_port,
jsonPayload.connection.protocol
FROM
`your_table_id`
GROUP BY
jsonPayload.src_vpc.vpc_name,
jsonPayload.src_vpc.subnetwork_name,
jsonPayload.connection.src_ip,
jsonPayload.connection.src_port,
jsonPayload.connection.dest_ip,
jsonPayload.connection.dest_port,
jsonPayload.connection.protocol
ORDER BY
bytes DESC
LIMIT
15
```

8.  Click **Run**.
    

**Note:** The results table shows the total bytes sent, source IP address, destination IP address, destination port, protocol, and the respective vpc name and subnet name.

**Note:** If you get an error, ensure that you did not remove the **#standardSQL** part of the query. If it still fails, ensure that the TABLE\_ID did not include the Project ID.with

Which columns do the results table contain?Source IP address and portDestination IP address and portProtocolVPC nameSubnet nameSum of bytes sent

**Submit**

### Analyze the VPC Flow Logs in BigQuery

The previous query gave you the same information that you saw in the Cloud Console. Now change the query to identify the top IP addresses that have exchanged traffic with your **web-server**.

1.  Create a new query in the Query Editor with the following and replace **your\_table\_id** with `TABLE_ID` while leaving the accents (\`) on both sides:
    

```apache
#standardSQL
SELECT
jsonPayload.connection.src_ip,
jsonPayload.connection.dest_ip,
SUM(CAST(jsonPayload.bytes_sent AS INT64)) AS bytes,
jsonPayload.connection.dest_port,
jsonPayload.connection.protocol
FROM
`bq_vpc_flows.your_table_id`
WHERE jsonPayload.reporter = 'DEST'
GROUP BY
jsonPayload.connection.src_ip,
jsonPayload.connection.dest_ip,
jsonPayload.connection.dest_port,
jsonPayload.connection.protocol
ORDER BY
bytes DESC
LIMIT
15
```

2.  Click **Run**.
    

**Note:** The results table now has a row for each source IP and is sorted by the highest amount of bytes sent to the **web-server**. The top result should reflect your Cloud Shell IP address.

**Note:** Unless you accessed the **web-server** after creating the export sink, you will not see your machine's IP Address in the table.

Feel free to generate more traffic to the **web-server** from multiple sources and query the table again to determine the bytes sent to the server.

## Task 5. Add VPC flow log aggregation

You will now explore a new release of [VPC flow log volume reduction](https://cloud.google.com/vpc/docs/using-flow-logs#log-sampling). Not every packet is captured into its own log record. However, even with sampling, log record captures can be quite large.

You can balance your traffic visibility and storage cost needs by adjusting specific aspects of logs collection, which you will explore in this section.

### Setting up aggregation

1.  In the Console, navigate to **Navigation menu** () > **VPC network** > **VPC networks**.
    
2.  Click **vpc-net**, and then click **Edit**.
    
3.  In the Subnets tab, click **vpc-subnet**:
    

![vpc-subnet highlighted within the Subnets tabbed page.](https://cdn.qwiklabs.com/%2FyuFy1yWkSiNiF9P0FFdqJfG4PlvURoLdrHNNNV5VdA%3D align="left")

4.  Click **Edit** > **Configure logs** to expose the following fields:
    

![Configure flow logs page with several fields displayed.](https://cdn.qwiklabs.com/1VOLuVc2prhOLvrgAkzjD5awfBHOXu%2FMDO0iJZkMt1E%3D align="left")

The purpose of each field is explained below:

*   **Aggregation time interval**: Sampled packets for a time interval are aggregated into a single log entry. This time interval can be 5 sec (default), 30 sec, 1 min, 5 min, 10 min, or 15 min.
    
*   **Metadata annotations**: By default, flow log entries are annotated with metadata information, such as the names of the source and destination VMs or the geographic region of external sources and destinations. This metadata annotation can be turned off to save storage space.
    
*   **Log entry sampling**: Before being written to the database, the number of logs can be sampled to reduce their number. By default, the log entry volume is scaled by 0.50 (50%), which means that half of entries are kept. You can set this from 1.0 (100%, all log entries are kept) to 0.0 (0%, no logs are kept).
    

5.  Set the **Aggregation Interval** to **30 seconds**.
    
6.  Set the **Sample rate** to **25%**.
    
7.  Click **Save**. You should see the following message:
    

![The estimated logs generated per day: 6.14 MB message.](https://cdn.qwiklabs.com/wiARwJ%2Fil38MiHfiVkBetQdhw%2FlmPmUPem0srofJVRQ%3D align="left")

Setting the aggregation level to 30 seconds can reduce your flow logs size by up to *83%* compared to the default aggregation interval of 5 seconds. Configuring your flow log aggregation can seriously affect your traffic visibility and storage costs.

* * *

## Solution of Lab

%[https://youtu.be/APkFf9-1On0] 

**🚨Copy and run the commands below in Cloud Shell:**

```apache
curl -LO raw.githubusercontent.com/ePlus-DEV/storage/refs/heads/main/labs/GSP212/lab.sh
source lab.sh
```

**Script Alternative**

```apache
curl -LO raw.githubusercontent.com/prateekrajput08/Arcade-Google-Cloud-Labs/refs/heads/main/VPC%20Flow%20Logs%20-%20Analyzing%20Network%20Traffic/TechCode.sh
sudo chmod +x TechCode.sh 
./TechCode.sh
```

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1756200819341/401c4b3b-b228-462a-93c6-742b0ea5213c.png align="center")

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1770171588224/3e86385d-7b50-4d36-b9c9-8b7346d1faf7.png align="center")

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1756200846934/e00e01d7-6a29-4e56-a407-1c009e481693.png align="center")

*   Sink Name: **vpc-flows**
    
*   BigQuery dataset: **bq\_vpc\_flows**
    

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1756200853754/c25d7bc9-cc70-47bd-9180-6c05c90fe59b.png align="center")

![](https://cdn.hashnode.com/res/hashnode/image/upload/v1756201014203/4ad94b62-ee2e-48fb-ad06-5254fd7e36f7.png align="center")

* * *

```apache
CP_IP=$(gcloud compute instances describe web-server --zone=$ZONE --format='get(networkInterfaces[0].accessConfigs[0].natIP)')

export MY_SERVER=$CP_IP

for ((i=1;i<=50;i++)); do curl $MY_SERVER; done
```