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Generate Trafic

IP traffic going to and from network interfaces in VPC A is now being collected in CloudWatch. Generate some traffic between the VPC A Private AZ1 Server Amazon EC2 instance in VPC A, and the VPC B Private AZ1 Server instance in VPC B using iperf (a widely used tool for network performance measurement and tuning).

After generating the traffic, continue to the next step to view the flow log in CloudWatch.

Review Security Group for EC2 instance in VPC B

A Security Group rule for the Amazon EC2 instance in VPC B has been created for you to allow the iperf server to receive incoming traffic.

  1. In the EC2 Dashboard navigate to Instances

  2. Select the check box next to the VPC B Private AZ1 Server instance, scroll down and click on the Security tab below and click on the Security groups link for sg-xxxxxxxx (VPC B Security Group)

    Security Group Link

  3. In the Security Group screen that opens scroll down to the Inbound rules tab and confirm that port 5201 is open for TCP traffic from 10.0.0.0/8

    Security Group Screen

    Install and run iperf3 server on EC2 instance in VPC B

  4. In the EC2 Dashboard navigate to Instances

  5. Select the check box next to the VPC B Private AZ1 Server instance, click Connect

    VPC B Instance

  6. Click Connect again in the Session Manager tab to open a command prompt

    Session Manager

  7. Install and start the iperf server on the EC2 instance in VPC B: 

sudo dnf install iperf3 -y && iperf3 -s

Install iperf

  1. Leave the Session Manager browser tab open, switch back to the Connect to instance tab and click on the Instances link

    Instances Link

  2. Select the check box next to the VPC A Private AZ1 Server instance, and click Connect

    VPC A Instance

  3. Click Connect again in the Session Manager tab to open a command prompt

    Session Manager

  4. Install iperf and set up a TCP transfer with 2 parallel streams for 30 seconds to the EC2 instance in VPC B.

sudo dnf install iperf3 -y && iperf3 -c 10.1.1.100 -P 2 -t 30

Connecting to host 10.1.1.100, port 5201  
[  4] local 10.0.1.100 port 37860 connected to 10.1.1.100 port 5201  
[  6] local 10.0.1.100 port 37862 connected to 10.1.1.100 port 5201  
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd  
[  4]   0.00-1.00   sec  64.9 MBytes   544 Mbits/sec   18    429 KBytes  
[  6]   0.00-1.00   sec  57.5 MBytes   482 Mbits/sec   16    380 KBytes  
[SUM]   0.00-1.00   sec   122 MBytes  1.03 Gbits/sec   34  
- - - - - - - - - - - - - - - - - - - - - - - - -  
[  4]   1.00-2.00   sec  59.6 MBytes   500 Mbits/sec   15    322 KBytes  
[  6]   1.00-2.00   sec  59.0 MBytes   495 Mbits/sec   25    256 KBytes  
[SUM]   1.00-2.00   sec   119 MBytes   994 Mbits/sec   40  
- - - - - - - - - - - - - - - - - - - - - - - - -  
[  4]   2.00-3.00   sec  64.6 MBytes   542 Mbits/sec   20    330 KBytes  
[  6]   2.00-3.00   sec  55.4 MBytes   465 Mbits/sec   23    223 KBytes  
[SUM]   2.00-3.00   sec   120 MBytes  1.01 Gbits/sec   43  
- - - - - - - - - - - - - - - - - - - - - - - - -  
[  4]   3.00-4.00   sec  49.6 MBytes   416 Mbits/sec   25    280 KBytes  
[  6]   3.00-4.00   sec  69.3 MBytes   581 Mbits/sec   15    272 KBytes  
[SUM]   3.00-4.00   sec   119 MBytes   998 Mbits/sec   40  
- - - - - - - - - - - - - - - - - - - - - - - - -  

...  

- - - - - - - - - - - - - - - - - - - - - - - - -  
[  4]  28.00-29.00  sec  59.7 MBytes   501 Mbits/sec   13    396 KBytes  
[  6]  28.00-29.00  sec  54.9 MBytes   460 Mbits/sec   14    330 KBytes  
[SUM]  28.00-29.00  sec   115 MBytes   961 Mbits/sec   27  
- - - - - - - - - - - - - - - - - - - - - - - - -  
[  4]  29.00-30.00  sec  62.9 MBytes   528 Mbits/sec   11    330 KBytes  
[  6]  29.00-30.00  sec  51.4 MBytes   431 Mbits/sec   17    289 KBytes  
[SUM]  29.00-30.00  sec   114 MBytes   959 Mbits/sec   28  
- - - - - - - - - - - - - - - - - - - - - - - - -  
[ ID] Interval           Transfer     Bandwidth       Retr  
[  4]   0.00-30.00  sec  1.78 GBytes   508 Mbits/sec  412             sender  
[  4]   0.00-30.00  sec  1.77 GBytes   508 Mbits/sec                  receiver  
[  6]   0.00-30.00  sec  1.66 GBytes   474 Mbits/sec  441             sender  
[  6]   0.00-30.00  sec  1.66 GBytes   474 Mbits/sec                  receiver  
[SUM]   0.00-30.00  sec  3.43 GBytes   983 Mbits/sec  853             sender  
[SUM]   0.00-30.00  sec  3.43 GBytes   982 Mbits/sec                  receiver  

iperf Done.
  1. When iperf completed with an iperf Done. message, terminate the Session Manager connection on the VPC A instance and switch to the Session Manager tab for the connection to the VPC B instance and terminate that session too.

You have successfully generated traffic between the two instances. The next step is to view the flow log in CloudWatch.