NAT Instance
Requirement:
Create EC2 instance in private Subnet and provide Internet
access using NAT Instance
Solution:
1.
Create One VPC with CIDR Range 10.0.0.0/16
2. Create a private Subnet with CIDR Range
10.0.1.0/24
3. Create a public Subnet with CIDR Range
10.0.2.0/24
4. Create One Internet Gateway and assign to VPC.
5. Create one custom Route table and associate
Public Subnet.
a.
Create a global route (0.0.0.0/0) and target to
IGW
6. Associate private subnet to default Route table
7. Launch the Nat instance using the template from
Community AMIs in public Subnet with Public IP enabled.
8. Select the Nat Instance created à Action à
Networking à Change Source/Dest. Check à
Yes,
Disable button.
9. Launch another EC2 instance in private Subnet
with only Private IP.
10. Note the Instance
ID of the NAT Instance and identify the Network Interface ID from Network Interface link in left hand pane.
11. Navigate to VPC à
Route Tables à
default Route table à
Routes
12. Add the global route (0.0.0.0/0) and select
Network Interface in Target dropdown. Choose the Network Interface ID noted
above then click on Save routes
button.
13. Login to Nat instance and SSH to EC2 private IP
and test the internet.
Note:
You must copy the pem file used for EC2 instance and change the permission to
400
chmod 400 <pem file>
ssh -i <pem file> ec2-user@<private IP of EC2>
[ec2-user@ip-10-0-1-211 ~]$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of
data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=50
time=3.22 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=50
time=3.44 ms
Points to Note:
NAT Gateway & Nat Gateway is specific to AZ, however it
can be shared the subnet in other AZ. Its always targeted to Public Subnet.
NAT Gateway needs one elastic IP and its chargeable.
Difference between NAT Gateway & NAT Instance
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