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In the previous video, we have done configuring
default route on router 3.

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Next in this video, we are going to configure nat so all client will
able to ping to internet. Okay let’s just start.

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To configure nat, first
we need to define the private ip address

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using access list. In this case, the
private ip address is vlan 10 and vlan 20,

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Let’s create the access list,
access-list 1 permit 192.168.10.0

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0.0.0.255, this is for vlan 10,
next let’s also create for vlan 20,

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Access-list 1 permit 192.168.20.0 0.0.0.255.

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Next, to configure nat, the command
is ip nat inside source list 1

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interface this is the public interface,
which is fa0/0, and then overload.

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This command means, that the router will doing a
nat from list 1, list 1 is vlan 10 and vlan 20,

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so vlan 10 and vlan 20 will be translated to the
ip address of fa0/0. In this case 10.20.20.2.

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so now if the client go to internet, the
original source address is 192.168.10.2,

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but after pass the router, the source
address will be translated to 10.20.20.2

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and then overload means that many private
ip address will be translated to only one

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public ip address, here we can see that we
have many client with private ip address,

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but we only have 1 public ip address.

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So we need to use overload here, to translate many
private ip address become 1 public ip address.

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Next we need to define all of interface
become nat inside or nat outside.

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Let’s start with fa0/0, so interface fa0/0

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This interface is connected to the internet, so
this will be nat outside, so here ip nat outside.

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Next, go to sub interface for vlan 10, interface
fa0/1.10, this interface is connected to internal,

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so we need to define this interface become
nat inside, the command is ip nat inside.

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Let’s also define sub interface for vlan 20 as
nat inside, interface fa0/1.20, ip nat inside.

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Okay we have done configuring nat.

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Now let’s try ping from client to internet or
google, pc0 to gooogle, okay this is success.

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Let’s also test from vlan 20, ping
172.16.10.2, okay this is also success.

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Okay so now we have done configuring nat.

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I think enough for this video

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Thank you for watching and see you on the next video .