We would like to know if its possible to make our on-premise firewall the NAT instance for the private instance in AWS VPC for outbound internet access (to get updates for example)?
We currently have AWS VPC scenario 4 implemented.
Thanks!!
For Scenario 4: VPC with a Private Subnet Only and Hardware VPN Access, all outbound (non-VPC) traffic has to go through the customer gateway to on-prem. So if you want to access internet, the traffic goes through on-prem and then outbound from on-prem/corporate network.
In short: From AWS VPC, if you want to access any AWS endpoint, you have to go through the corporate/customer network. You have to allow outbound in your on-prem firewall. There is no other option.
If you really want to access internet through NAT, you should have created Scenario 3: VPC with Public and Private Subnets and Hardware VPN Access
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I am currently working on a ETL tool at work (python & bash scripts managed with Airflow basically) and I am asking myself wether I should put my EC2 instance which will run the ETL in a public or private subnet. My instance should have acces to the internet to retrieve data (basically ssh through on-premises instances we have) and should also be able to be accesses through SSH.
However, I don't know if allowing outbound connection to the internet and restrict inbound connection to SSH is enough about security or if I should put the instance in a private subnet and tweaking things to be able to connect to it.
Your ETL instance should be in a private subnet behind a NAT instance.
NAT gateway will give your EC2 private network internet connectivity but still ensure that your EC2 instances are not accessible from the internet. So in order to allow access to internet it has to route traffic through public network which has a Internet gateway attached.
You should put your EC2 instance in a private subnet to prevent hackers from gaining access and stealing your data.
You can learn how to setup NAT gateway here
https://aws.amazon.com/premiumsupport/knowledge-center/nat-gateway-vpc-private-subnet/
As the main purpose of your instance is not to deliver a public service, it'd be more secure in a private subnet and go through a NAT gateway to fetch data from the Internet.
That being said a NAT gateway is expensive, so a common pattern is to use a public subnet/ through an Internet gateway with a deny rule for any incoming traffic. If you don't want your instance exposed to ddos, don't even open ssh and use AWS systems manager to ssh your instance.
Is there anyone who can explain me that situation below ?
I connected to Ec2 intance in private subnet via Bastion Host.Then I created a vpc gateway endpoint to reach s3. I assigned the required role to ec2 and the connection to s3 is done. My question is, how can Ec2 instance in private subnet download something from the internet?
A VPC endpoint is used to access a certain service, in this case S3, over the AWS network instead of over the internet.
If you want your instance to be able to talk to the internet, you'll need to configure a NAT gateway in a public subnet, and you'll need to configure the route table of the private subnet to forward traffic to the NAT gateway.
A simple solution would be:
Put everything in a Public Subnet
Assign a Public IP address to the Amazon EC2 instance
Use Security Groups to secure access on the Amazon EC2 instance (that is, only allow Inbound connections from the Bastion)
The effective result is the same as using a Private Subnet, but the EC2 instance will be able to establish Outbound connections to the Internet (but not Inbound, so it remains secure).
Anyone here that have a ec2 instance that is on a private subnet in AWS that is able to connect to outside FTP server? It seems that my ec2 instance cannot connect to 3rd party ftp servers without moving to public subnet and using elastic/public ip.
Private subnet by default have no connectivity to outside world or internet. But there is a resource called NAT Gateway that you can configure in your VPC to provide an outgoing internet connectivity from your private subnets.
You can use a network address translation (NAT) gateway to enable
instances in a private subnet to connect to the internet or other AWS
services, but prevent the internet from initiating a connection with
those instances.
You can follow the link here to setup the NAT gateway.
https://aws.amazon.com/premiumsupport/knowledge-center/nat-gateway-vpc-private-subnet/
Private subnets do not have internet connectivity by default. You need to create a nat gateway on the public subnet. Nat gateways are bit expensive. You can also create a nat instance in that case.
I have a private M2M GSM network for my company devices.
I want to send traffic from my devices to AWS IOT but the M2M provider doesn't allow internet access from its sim cards, it only provide an IPSec connexion to a a private network.
I had now problem configuring the IPSec connexion to an AWS VPC and my sims can successfully ping all instance in my AWS VPC. However what I want is for my sims to access AWS IOT.
What I did:
I configured my VPN with AWS third scenario. I have a public network with CIDR 192.168.0.0/24 and a private network with CIDR 192.168.1.0/24. My VPN has a static route CIDR 10.1.128.0/14 for my M2M network.
Then I launched an EC2 Nat Instance inside my public network.
I added a routing rule to my VPC main routing table to route trafic to 0.0.0.0/0 to my NAT instance.
I launched an EC2 instance in my VPC's private network and try to access internet from it, this work and I can see trafic going throung my nat instance. So I assume my nat and routing is well configured.
However I still can't manage to access internet from my sim cards, traffic isn't even routed to my NAT instance. According to John Rotenstein's answer VPN traffic will not use my routing rule.
Does AWS VPN drop traffic which is not destinated to the VPC's or VPN's CIDR ? Is there a security reason for that ?
If that's the case is there a way to customize routing rules for the VPN's traffic ? Or is the only solution to use a custom VPN within an EC2 instance ?
Thank you for your help.
I added a routing rule to my VPC main routing table to route trafic to 0.0.0.0/0 to my NAT instance.
It is an understandable misconception that the "main" route table of a VPC impacts traffic coming in from a VPC hardware VPN. It doesn't. There is no route table that applies to such traffic, only the implicit target of the VPC subnets. Only the assigned CIDR blocks can be reached from such a VPN.
Does AWS VPN drop traffic which is not destinated to the VPC's or VPN's CIDR? Is there a security reason for that?
Yes, that traffic is dropped.
It probably not specifically for security reasons... it's just the way the service was designed to work. Managed VPN connections are intended for access to instance-based services, and don't support traffic flows we might generally categorize as gateway, edge-to-edge, peering, or transit.
If you can configure your edge devices to use a web proxy, then a forward proxy server like squid could handle the connectivity for the devices, because the IP path between a device and a forward proxy is a connection involving only the device and proxy IPs.
A simpler solution would be to use an instance-based firewall to terminate the VPN, instead of the built-in VPC VPN service, because then the firewall instance could allow the traffic to hairpin through itself, source-masquerading (NAT) the traffic behind its own EIP, and this would be something the VPC infrastructure easily supports.
An instance-based firewall is something you can build yourself, of course, but there are also several products in the AWS Marketplace that provide IPSec tunnel termination and NAT capability. Some have free trial periods where the only cost is the cost of the instance.
We're setting up an Amazon VPC in which we will provision (for now) a single EC2 instance and one RDS instance. This is to 'extend our data center', and should only be using private subnet(s).
So actually, we have this setup, and it is working well (insert smiley face icon). For all intents and purposes, we're mirroring the VPC scenario 4 outlined by Amazon here: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Scenario4.html
tl;dr: A single VCP, with a VPN connecting to our corporate network. The VPN uses a Virtual Private Gateway (VPC end) and Customer Gateway (our end) to allow us access as necessary to the EC2, which contains a webserver connecting to the RDS instance as needed. Anyone on our network has access to the web server running on the EC2 via a URL. All this is working as expected.
The problem comes when the EC2 instance needs to access a resource on the Internet - The idea is for us to NOT have any public subnets, but to route all traffic from the EC2 instance through our VPN and out the 'standard' path of our corporate Internet access. However we're having trouble setting this up.
The fact that it can be done is hightlighted in Amazon's FAQ here:
https://aws.amazon.com/vpc/faqs/
Q. How do instances without public IP addresses access the Internet?
Instances without public IP addresses can access the Internet in one of two ways:
Instances without public IP addresses can route their traffic through a NAT gateway or a NAT instance to access the Internet. These instances use the public IP address of the NAT gateway or NAT instance to traverse the Internet. The NAT gateway or NAT instance allows outbound communication but doesn’t allow machines on the Internet to initiate a connection to the privately addressed instances.
For VPCs with a hardware VPN connection or Direct Connect connection, instances can route their Internet traffic down the virtual private gateway to your existing datacenter. From there, it can access the Internet via your existing egress points and network security/monitoring devices.
We are trying to avoid option #1 as there is a cost involved (along with complexity and security issues). #2 is the perfect resolution for us, but understanding the process to set it up has been eluding us for a while.
Can anyone walk us through what we need to do (or point us to the correct resources) to ensure the EC2 instance* can access the Internet by routing the traffic down the VPN, through our corporate datacenter, and our our existing Internet access point?
* and anything within the private subnet for that matter
If you are using scenario #2, then all there is to do on the AWS end is to ensure that traffic destined for the internet, 0.0.0.0/0 is routed to your Virtual Private Gateway.
Once traffic heads there, it will go to your Customer Gateway, and into your corporate datacenter. It's up to your local IT guys on that end to get Internet-destined traffic heading out, if it's even possible. But at that point, it's no longer an AWS issue.