NAT Gateway Note

 // nat

1 dipake buat koneksi private ip  ke internet

2 dipake klo ada ip private network yg bentrok / sama dan ingin koneksi keluar

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// nat instances vs nat gateway

nat instances = individual ec2 instance.

- bs down nat instances

- mesti bikin lebih dr 1 

// nat gateways

- manage service which launches redundant instances within the selected AZ.

- di manage sama aws

- ada redundansi dibalik layar. aws yg manage.

** nat instances hrs ada di public subnet.

ec2 -> ada di private subnet

^ semua nat jalan per AZ

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// nat instancce and nat gateway note++

// note nat instance

- pas bikin  nat mesti disable source and destination checks di instance

- nat instances mesti ada di public subnet

- hrs ada route out dari private subnet ke nat instance 

- ukuran nat instance determine seberapa besar traffic bisa dihandle

- high availability bs pake autoscalling group, multiple subnet di AZ yg berbeda, dan automate failover pake script   =>  lebih repot dibanding nat gateway

// note nat gateway

- bersifat redundant didalam sebuah AZ.

- cm boleh punya 1 nat gateway didalem 1 AZ / ga bs dispan

- start dr 5Gbps dan bisa discale up ke 45Gbps

- Nat Gateway dipake buat enterprise

- ga perlu ngepatch nat gateawy. ga perlu disable source/destination checks 

- nat gateway otomatis diassign public ip

- route tables for nat gateway mesti di update

- resource di multiple AZ sharing gateway will  lose internet access if gateway goes down, unless u create a gateway in each AZ and configure  routes accordingly

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