I have the following Lambda function set in AWS which have to return the params of
AWS Network Firewall:
import boto3
import json
session = boto3.session.Session()
nf_client = session.client(
service_name = "network-firewall",
endpoint_url= "https://network-firewall.eu-west-2.amazonaws.com"
)
def lambda_handler(event, context):
response = nf_client.describe_firewall(
FirewallName="DemoFirewall2")
return 1
What I have checked
It timeouts no matter the timeout limit
The alocated memory is enough
Both endpoints of the lambda and the firewall can be reached from one another(even checked with Network Analyzer)
Security groups are allowing all trafic in both directions.
The lambda is associated to the VPC and with the sub-net of the firewall.
CloudWatch is showing just timeout.
I have no additionl configration, no environment variables or such just what is defined in the lambda.
I have two subnets and 4 routing tables:
client subnet which has the following routing table and it is associated with the according subnet:
10.1.0.0/16 local
0.0.0.0/0 vpce-firewallEndpoint
Firewall subnet associated with the accordig subnet:
10.1.0.0/16 local
0.0.0.0/0 igw-InternetGateway
Gateway table with edge association to the gateway:
10.1.0.0/16 local
10.1.2.0/24 vpce-firewallEndpoint
the deafault main table:
10.1.0.0/16 local
The traffic from the client subnet is routed to the firewall subnet and then routed to the IGW.
Guess I am missing something with the session configarion because the lambda probably don't know which firewall to describe.
Lambda functions in a VPC never get assigned a public IP address, so they can't use an Internet Gateway directly. A Lambda function in a VPC has to be deployed in a private subnet, with a route to a NAT Gateway, in order to access things outside the VPC.
If your Lambda function doesn't need to access any VPC resources then there is no benefit to deploying the function inside the VPC, it only causes issues such as the one you are encountering.
Related
I currently have a lambda function which is inside a Private VPC because I am using it to access a ElasticCache Redis Cluster. However, I am unable to make https requests because of the private VPC.
I have greated a NAT gateway with one of the subnets but all https requests time out.
Should I be creating a second lambda function? How should I be doing this?
The configuration should be:
NAT Gateway connected to a public subnet
AWS Lambda function connected to a private subnet
Private subnet Route Table configured to point to the NAT Gateway for 0.0.0.0/0 destination
Security Group on the Lambda function with "Allow All" Outbound rules
Adding ip address of the server you are trying make an https to, to the outbound rules of the security group might help. The outgoing request must've been disabled.
My lambda is getting ETIMEDOUT for hostname s3.amazonaws.com. I figured out that is is probably caused by the fact that my lambda is inside a VPC.
I suspect that I need to use an AWS Endpoint to reach S3. I know that we have endpoint set up and in AWS Console I can see and endpoint associated with this VPC called dev-s3-gateway with service name com.amazonaws.us-east-1.s3
How do I tell my lambda to use this endpoint?
Inside a VPC, your Lambda can be in either a private subnet or a public subnet.
Lambda in Public Subnets CANNOT access the internet.
Having Lambda access the internet
Being in a Private Subnet, your Lambda cannot have "direct" access to the internet. You need to provision a Public Subnet in your VPC and have both an Internet Gateway as well as a NAT Gateway in that subnet.
Route the traffic to 0.0.0.0/0 from your Lambda's subnet via the NAT Gateway.
From the routing table of the Public Subnet, route traffic to 0.0.0.0/0 via the Internet Gateway.
Your Lambda should now have access to the internet (and to S3).
Feel free to also check out this more detailed guide.
Accessing AWS services through VPC endpoints
Several AWS services offer VPC endpoints. These allow you to connect and interact with the respective services without your traffic ever leaving the AWS network.
For more information on them, please check out their documentation.
EDIT: Expanding a bit on your specific S3 use case.
S3 offers Gateway and Interface VPC Endpoints. Based on the endpoint name you provided in the question, I'm going to guess this is a Gateway VPC Endpoint. Once you set up the endpoint in your VPC, the Security Group(s) associated with your Lambda must allow outbound traffic to the endpoint.
You have two options.
First and simplest (but perhaps less secure - depending on your use case), you allow outbound traffic to 0.0.0.0/0. This will effectively allow you to call anything. However, if the Lambda is in a public subnet, it won't be able to access the internet, as explained above, but rather only the Gateway VPC Endpoint ranges.
The second option is to allow outbound traffic to the known Prefix List of the regional Amazon S3 endpoint. You can retrieve the PrefixList ID (looks like pl-xxxxxx) by invoking the DescribePrefixLists and looking for that Prefix List for service com.amazonaws.us-east-1.s3. Once you have the ID of the Prefix List, you can add it to the destination of an outbound rule of your Security Group(s).
How can I create a VPC/subnet on AWS and launch a Windows instance and Linux instance in that same subnet. whenever I try to create a vpc it will not give ssh access to other terminals even though I give permissions in route tables.
This could be many things. I'd probably recommend looking at security groups (adding TCP/22 inbound from your IP address) and depending on your setup (make sure an IGW is attached), making sure a public IP address is assigned to your instances (add an Elastic IP if your instance doesn't already have one). Without more information on your environment, I can only provide some background to help you troubleshoot.
The network path to an instance in a VPC looks like this:
Internet -> AWS Boundary -> VPC Boundary -> VPC Router -> Subnet boundary -> Elastic Network Interface
AWS Boundary
Most of the time this part isn't important. From the Internet, eventually your traffic will be routed into an Amazon autonomous system. This is generally transparent. But if you have a public-type Direct Connect, the Amazon side of the connection dumps you here. In this area, you can access public API endpoints, but you cannot access anything within a VPC without progressing further down the stack. See below.
VPC Boundary
This is the point at which traffic enters/leaves the VPC. There are a number of ways this can occur.
Internet Gateway (IGW)
This performs a one-to-one NAT between an amazon-owned publicly routable IP address and a VPC internal private IP address (do not confuse this with a NAT Gateway, as that's different and described below). Only instances assigned a public IP address can use an IGW. Being a 1-to-1 NAT, to the Instances perspective it's a connection between it's private IP address and an Internet-routable IP. From the outside it's a connection to the instance's public IP address. To stress, instances without a public IP address assigned (elastic IP or otherwise) will not be able to communicate with the Internet in either direction through an IGW. Conversely, if you don't have an IGW, there is no use for public IP addresses on your instances. Also worth mentioning, there are also egress-only gateways which allow IPv6 connectivity for outbound initiated connections only.
Virtual Private Gateway (VGW)
This can be seen as a router of sorts. If you have a VPN connecting to AWS' VPN service or if you're using Private Direct Connect, it will traverse this virtual device, which will be associated with a VPC. What's noteworthy, is that is a peering of sorts and uses VPC private IP addresses for communication. You don't need a public IP address to talk through a VGW, and you cannot traverse a VGW by using the public IP address of instances in your VPC.
VPC Peering Connections (PCX)
This is very similar to a VGW. It can only connect two VPCs (with transit gateway, I suppose this is an oversimplification), and it connects them on the Private IP address layer. You cannot reference resources across a PCX by using their Public IP addresses.
VPC Endpoint (VPC-E)
This is only accessible from inside of the VPC with connections going out (obviously return traffic with come back through this, but . It is a connection to a specific AWS Endpoint within the AWS Public Boundary (like the S3 API endpoint). This doesn't use an instance's public IP address.
VPC Router
All traffic exiting or entering the VPC hits this router, and it routes to/from all of the egress/ingress points at the VPC boundary and to/from each of the subnets. You can adjust this router to control which traffic goes where, and you can have different route tables for each subnet. Thus a "public" subnet is one in a VPC that has a IGW and has a default route (0.0.0.0/0) to that IGW. A private subnet has no route to an IGW. If there isn't a route to an IGW, having a public IP address on your instance is useless and wasteful.
You can also route to an ENI if you want to control traffic within your VPC and send it to an EC2 Instance (web proxying / IDS / traffic capturing / etc.), however, that ENI has to reside in a subnet with a different route table, or otherwise it's own outbound traffic will be routed back to itself. All traffic exiting/entering any subnet and all traffic exiting/entering the VPC traverses this router and is subject to the routes you configure. You cannot configure routing within your subnets, any packet destined for an address within your VPC's private IP space will be automatically routed to that particular subnet, and you cannot override this functionality with more specific routes.
Subnet Boundary
At the subnet boundary, traffic is subject to the Network Access Control Lists (NACLs). This is a stateless, rule-based firewall. By default it is wide-open and requires no configuration to allow traffic. There is no rule to allow "existing connections" so if you start to lock down a subnet with NACLs, you'll probably need to open up all of the ephemeral ports in the direction you're expecting return traffic. Any traffic between instances within the same subnet will not hit the NACL. But anything that leaves or enters the subnet (whether it's going to another subnet in the same VPC, or leaving the VPC altogether) will hit the NACL and be subject to its rules. Generally leave these alone, unless you need to protect traffic at the subnet level, NACLs are a little unwieldy.
Elastic Network Interface (ENI)
Finally traffic goes through an ENI, where it is subject to a security group. This is a stateful implicit-deny firewall for which you can only add allow rules. If the security group doesn't have a rule allowing outbound traffic from the instance, that traffic will never leave the ENI. If the security group doesn't have a rule allowing a kind of inbound traffic, that kind of inbound traffic will never be sent to the Instance (i.e. the OS will not be able to detect it).
NAT Gateway
This is a device that can reside in a subnet. It will need a route to an IGW and it will need a public IP address (Elastic IPs work). It performs a many-to-one NAT of any private IP addresses within your VPC to a publicly-routable IP (technically it performs a many-to-one NAT translating the many private IP addresses within your VPC to its one own private IP address, and when it communicates with the IGW, that does a one-to-one NAT to translate the NAT Gateway's private IP address into a public IP address). This only works for IPv4. And it only works if instances send their traffic to the NAT Gateway's ENI. Generally, you'd have a NAT Gateway reside in a public Subnet (with a default route to the IGW), and all of your instances in private subnets would have a default route to the NAT Gateway's ENI.
Summary
Bare minimum to connect to an EC2 Instance:
VPC has an IGW attached
NACL has allow rules for the desired traffic in both directions (configured by default)
EC2 Instance has a security group allowing the desired traffic (TCP/22 for SSH, etc.)
EC2 Instance has a public IP address associated with it (must be configured when you launch the instance, or can be added afterward by attaching an Elastic IP).
This configuration allows you to directly connect to the instance over the public internet.
Well-Architected VPC Pattern
The generic architectural pattern advised by AWS for simple best-practice networks is:
VPC with an IGW attached
two-or-more public subnets (each in separate availability zones) with a default route to the IGW.
a NAT Gateway in each of the public subnets
two-or-more private subnets (each in the same AZ as the public subnets) each with default routes to the NAT Gateway in the public subnet in the same AZ.
a bastion host in an auto-scaling group of 1 spanning all of the public subnets allowing SSH inbound (Whether this is advisable is debatable)
if needed, a VPN connection from your corporate network to the VPC
security groups on the private instances allowing inbound from specific resources within the VPC (referencing by security group ID where possible) and whatever inbound traffic is needed through the VPC, and outbound traffic TCP/443 outbound to the world (or more/less depending on your risk tolerance and needs).
if needed, and VPC Endpoint to S3 or whatever API endpoints you expect to send large volumes of traffic.
This architecture allows your private instances to connect to public internet resources outbound (using IPv4, at least), and inbound traffic has to go through the VPN or the bastion host. For public-facing services, setting up an Elastic Load Balancer in the public subnets is the desired way to provide public connectivity for your instances, so that you can continue to keep them protected in a private subnet.
i want to send mail using node mailer in NodeJS if my lambda function is developed in default VPC because I have to access RDS too from the lambda function.
I am unable to send success mail for data successfully inserted in RDS if I deployed my lambda function in default VPC WHAT changes I need to do so I can send.
IF I choose NO vpc then I am unable to set data to database.
From https://docs.aws.amazon.com/lambda/latest/dg/configuration-vpc.html,
When you connect a function to a VPC in your account, it does not have access to the internet unless your VPC provides access.
I take this to mean that if you wish to access both RDS and the internet from lambda from within your VPC, you need a NAT gatway (or to spin up your own instance). In other words, lambda does not support internet access with a public IP through an Internet Gateway, which is the mechanism of internet access within your vpc.
If you don't mind the cost, about 4.5 cents an hour plus data transfer last I checked, the simplest solution is probably:
add another subnet to your VPC.
Add a NAT Gateway to your VPC.
Add a route table to the subnet that routes through the NAT Gateway
put your lambda in that subnet
This essentially creates a connection to the internet in that VPC without your lambda holding a Public IP address.
I am trying to connect to my Redshift database (located in N. Virginia region) from Lambda function (located in Ireland region). But on trying to establish a connection, I am getting timeout error stating:
"errorMessage": "2019-10-20T13:34:04.938Z 5ca40421-08a8-4c97-b730-7babde3278af Task timed out after 60.05 seconds"
I have closely followed the solution provided to the AWS Lambda times out connecting to RedShift but the main issue is that the solution provided is valid for services located in same VPC (and hence, same region).
On researching further, I came across Inter-region VPC Peering and followed the guidelines provided in AWS Docs. But after configuring VPC Peering also, I am unable to connect to Redshift
Here are some of the details that I think can be useful for understanding the situation:
Redshift cluster is publicly accessible, running port 8192 and has a VPC configured (say VPC1)
Lambda function is located in another VPC (say VPC2)
There is a VPC Peering connection between VPC1 and VPC2
CIDR IPv4 blocks of both VPCs are different and have been added to each other's Route tables (VPC1 has 172.31.0.0/16 range and VPC2 has 10.0.0.0/16 range)
IAM Execution role for Lambda function has Full Access of Redshift service
In VPC1, I have a security group (SG1) which has an inbound rule of type: Redshift, protocol: TCP, port: 5439 and source: 10.0.0.0/16
In VPC2, I am using default security group which has outbound rule of 0.0.0.0/0
In Lambda, I am providing private IP of Redshift (172.31.x.x) as hostname and 5439 as port (not 8192!)
Lambda function is in NodeJS 8.10 and I am using node-redshift package for connecting to Redshift
After all this, I have tried accessing Redshift with both public IP as well as through its DNS name (with port 8192)
Kindly help me out in establishing connection between these services.