On PC1, Select the Command Prompt and enter the commands as shown in exhibit below:

On PC2, Select the Command Prompt and enter the commands as shown in exhibit below:

On PC4, Select the Command Prompt and enter the commands as shown in exhibit below:

On PC3, Select the Command Prompt and enter the commands as shown in exhibit below:

On PC3, change the subnet mask to 255.255.255.0. When it is set to 255.255.255.128, then the PC with a .129 address will not be on the same subnet as the default gateway which is .1 On PC4, change the default gateway to 10.0.2.1. It has been incorrectly set as 10.1.2.1.