I have a pretty simple question that drives me nuts. I am trying to understand how VPC router (routing tables) and ELB interact with another.
I read documentation and tried understanding it, but without success. My current understanding of a VPC is pretty much like this:
Data passes the I-GW
The I-GW uses the VPC router and its routing tables to forward the request/traffic to the ELB.
The ELB is used to address e.g. EC2 instances
What I think I got from the internet:
Data passes the I-GW
The ELB is using listeners to determine incoming traffic (e.g. Port 80)
ELB is forwarding the traffic to the instances.
Updated by adding diagram (sry, I did not earn the privileges to upload one directly). :(
enter image description here
VPC or subnet route tables are used for routing packets originating within the VPC/ subnet i.e. outbound traffic NOT inbound traffic. Traffic to AWS ELB DNS name is resolved to an IP address via DNS resolution + IP routing (IP routing) to reach destination. Traffic from your VPC is routed using route tables. Hope this helps
Related
I have a few elastic beanstalk applications on the same VPC (which can also be reduced to one application), and I'd like them to be accessible both via one IP address (both inbound and outbound traffic), and via their own URL. I've seen that this can be done via NAT, but I haven't found documentation on whether this is all traffic (in both directions) and if it can be done alongside the original endpoints. Another question is whether there is a better way to do this.
NAT is used to provide access to internet for instances in private subnets. In this case all instances in the subnet will have the same external IP. But you won't be able to access your private instances using that IP, it's only for outbound traffic.
In your case I'd go with a ELB. Following the best practices, keep your instances with running applications in private subnets and:
Have an external facing ELB in public subnets (you'll need at least 2 public subnets in different AZs).
Create a Target Group and add your instances with running apps to it.
Assign the Target Group to the listener on your ELB.
Configure the security groups on ELB and app instances to allow the traffic on the port the applications are serving (usually it's 8080).
As a result you'll have your instances accessible by the ELB URL. If you want to have a pretty URL, you can configure it in Route 53 and resolve it to the ELB URL.
Its not possible by using aws provided NAT cluster but can be achieved by hosting a box with both Load balancer and NAT running in the same instance with EIP, map your domain with that IP for incoming traffic, for outgoing traffic in the route table of private app subnet you configure the NAT as target for all the 0.0.0.0/0 route, But it is not the recommended approach since the front facing instance becomes SPOF.
The recommended way is using ELB as a front facing and NAT cluster as outgoing for high HA.
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.
Has someone configured a NLB in the public subnets of your VPC to route traffic to EC2 instances that are in the private subnets?
When using an ELB, a good solution is to create a Security Group for the ELB and then create another SecurityGroup for the private EC2 Instances, allowing incoming traffic from that ELB Security Group, as explained here:
https://aws.amazon.com/premiumsupport/knowledge-center/public-load-balancer-private-ec2/
"You can also add a rule on the instance’s security group to allow traffic from the security group assigned to the load balancer. For example, if the security group on the load balancer is sg-1234567a, make the following changes on the security group associated with the private instances"
Since you cannot associate a Security Group to a NLB, how could you accomplish this with the same type of security?
Thanks!
Since you cannot associate a Security Group to a NLB, how could you
accomplish this with the same type of security?
The security aspect does not change.
NLB is a different beast, it not the same as classic Load Balancers. For Classic Load Balancers, from the point of view of your instances, traffic does appear to come from inside the VPC. From outside, traffic goes to a (random and mutating) list of IP addresses, resolved by the DNS record that AWS provides to you.
Network Load Balancers are completely different. From the point of view of your instances, they are completely invisible. If it is an external network load balancer, traffic appears to be coming from instances on the internet directly (even though this is an illusion). Therefore, if you want to talk to everyone on the internet, 0.0.0.0/0 is what you open it to.
This is, in fact, what the documentation says:
https://docs.aws.amazon.com/elasticloadbalancing/latest/network/target-group-register-targets.html#target-security-groups
Recommended Rules
Inbound Source Port Range Comment
Client IP addresses instance listener Allow traffic from clients on the instance listener port
VPC CIDR health check Allow traffic from the load balancer on the health check port
Client IP addresses is whatever your client IPs are. If they are on the open internet, 0.0.0.0/0 it is. Adding the NLB private IP address, as I saw in other responses, accomplishes nothing. Traffic is not coming from there, as far as the instances are concerned.
On the security angle, nothing changes. Since your instances are in private subnets, traffic cannot flow directly to them, as there is a NAT gateway in the middle. It can only flow from them to the internet (through NAT gateway, then internet gateway). Even if you specify all traffic is allowed from everywhere, traffic still won't come. It will have to come through another way. In your case, that way is the NLB, which has a fixed number of ports it listens to, and only sends traffic to the destination ports on the instances you specify.
If you are moving from classic Load Balancers to NLBs, move the security group rules from the Load Balancer to your instances. Or better yet, since you can have multiple security groups, just add the SG you currently have for the classic LB to the instances(and update any ASGs as needed). Your security posture will be exactly the same. With the added benefit that now your applications won't need things like proxy protocol to figure out where traffic is coming from, it is no longer obfuscated by the load balancer.
That is indeed true as per AWS Documentation :
Network Load Balancers do not have associated security groups.
Therefore, the security groups for your targets must use IP addresses
to allow traffic from the load balancer.
So If you do not want to grant access to the entire VPC CIDR, you can grant access to the private IP addresses used by the load balancer nodes. There is one IP address per load balancer subnet.
On NLB Tab of there is one Network Interface per Load Balancer from there :
On the Details tab for each network interface, copy the address from
Primary private IPv4 IP.
You can use this private IP Address at add it SG of EC2 Instances.
Please Refer to AWS Documentation
Tail your http access logs and you will see there is no changing of source IP address from the network load balancer which means you need to allow 0.0.0.0/0 on the endpoints security group if the internet needs access to your endpoint.
This is only ok if you use a private subnet so be careful if you have this server on a public subnet as this solution would not be advisable. In this case just use an application load balancer. You can still setup the same listener and configure a target group by instance as well. The application load balancer will update the source IP address to it's own private address if you tail the access logs. The advantage of this is you only need to allow https traffic to the app load balancer and then you can accept http for the target group if you like from the load balancer.
I need the static IP to allow access to a firewalled network not on the AWS network.
Is it possible to get a static IP for a load balanced app using Elastic Beanstalk? I'm following the AWS docs regarding using Route 53 to host my app with a domain name, but from what I've read, this does not ensure a static IP because it is essentially using a CNAME allowing the IP behind the scenes to change. Is that the right understanding? Is it possible at all?
This post helped me get a static IP for outgoing requests by using a NAT Gateway, and routing specific requests through it.
I needed this static IP in order to be whitelisted from an external API provider.
I found this way much easier than the provided by AWS, without the need of creating a new VPC and a private and public subnets.
Basically, what I did was:
Create a new subnet to host the NAT Gateway.
Create the NAT Gateway in the above subnet, and assign a new Elastic IP. This one will be our outgoing IP for hitting external APIs.
Create a route table for the NAT subnet. All outbound traffic (0.0.0.0/0) should be routed through the NAT Gateway. Assign the created subnet to use the new route table.
Modify the main route table (the one that handles all our EC2 instances requests), and add the IP(s) of the external API, setting its target to the NAT Gateway.
This way we can route any request to the external API IPs through the NAT Gateway. All other requests are routed through the default Internet Gateway.
As the posts says, this is not a Multi AZ solution, so if the AZ that holds our NAT Gateway fails, we may lose connection to the external API.
Update:
See #TimObezuk comment to make this a Multi-AZ solution.
Deploy your beanstalk environment in VPC, and with the right configuration, a static IP for outbound traffic is easy.
In this setup, your instances all relay their outbound traffic through a single machine, which you can assign an elastic IP address to. All of the inside-originated, Internet-bound traffic from all of the instances behind it will appear, from the other network, to bw using that single elastic IP.
The RDS portion of the following may be irrelevant to your needs but the principles are all the same.
http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/AWSHowTo-vpc-rds.html
Deploy your beanstalk environment in VPC, and with the right configuration, a static IP for outbound traffic is easy.
In this setup, your instances all relay their outbound traffic through a single machine, which you can assign an elastic IP address to. All of the inside-originated, Internet-bound traffic from all of the instances behind it will appear, from the other network, to bw using that single elastic IP.
The RDS portion of the following may be irrelevant to your needs but the principles are all the same.
http://docs.aws.amazon.com/elasticbeanstalk/latest/dg/AWSHowTo-vpc-rds.html
I have a set-up running on Amazon cloud with a couple of EC2 Instances running through a load balancer.
It is important that the site has a unique(static) IP or set of IPs as I'm plugging in 3rd party APIs which only accept requests made from IPs which have been added to their whitelist.
So basically unless we can give these 3rd parties a static IP or range of IPs that the requests from the site will always come from then we would be unable to make any calls to them.
Anyone knows how to achieve this as I know that Elastic IPs are not compatible with load balancers?
If I were to look up the IP of the load balancer DNS name (e.g. dualstack.awseb-BAMobile-ENV-xxxxxxxxx.eu-west-1.elb.amazonaws.com resolves to 200.200.200.200) would that IP be Static?
Any help/advise is greatly appreciated guys.
The ip addresses of your load balancer is not static. In any event, your incoming load balancer IP wouldn't be used for outgoing connections.
You could assign elastic IPs to the actual instances behind the load balancer, which would then be used for outgoing requests. You get 5 free elastic ips, and I believe you can apply for more if you need them.
Additionally if using a VPC and if your instances are in a private subnet then they will only be able to access the internet via the NAT instance(s) you setup, and you can of course assign an elastic IP to the NAT instances
This is an old question, but things have changed now.
Now you can create a Network ELB to get a LB with a static IP.
from https://docs.aws.amazon.com/elasticloadbalancing/latest/network/introduction.html
Support for static IP addresses for the load balancer. You can also
assign one Elastic IP address per subnet enabled for the load
balancer.
https://aws.amazon.com/blogs/aws/new-network-load-balancer-effortless-scaling-to-millions-of-requests-per-second/
You can attache an additional ENI (Elastic Network Interface) to an instance in your VPC. This way the ELB (Elastic Load Balancer) routes the incoming Internet requests to the web server, and the additional ENI will be used to connect to your 3rd party (or internal) requests (Management network)
You can see more details about it in the VPC documentations
Really the only way I am aware of doing this is by setting up your instances within a VPC and having dedicated NAT instances by which all outbound traffic is routed.
Here is a link to the AWS documentation on how to set up NAT instances:
http://docs.amazonwebservices.com/AmazonVPC/latest/UserGuide/VPC_NAT_Instance.html
You CAN attach an elastic IP to the instances BUT NOT to the ELB (which is what the client sees).
You could use a full reverse proxy layer 7 load balancer like HAProxy:
Or a commercial implementation like Loadbalancer.org or Riverbed (Zeus)
They both are in the AWS Marketplace:
Your outbound requests to your 3rd party APIs will NOT go out via the ELB/ALB. That's for incoming connections. If you need an inbound static IP you'll probably need to forego the loadbalancer (or figure out how to implement Anshu's suggestion to attach an elastic IP to the loadbalancers, the doc is light on details). Update: I found some documentation that ALB use static addresses (and I just tried binding an elastic IP to one to be sure and that failed).
If you're talking about outbound connections see below:
If your server is deployed in a public subnet you can attach an
elastic IP to that host. Outbound communications will go out over
that address.
If your server is deployed in a private subnet there's
a NAT gateway attached to it. All outbound traffic from your private
subnet will go out over that interface.
You could use as already mentioned loadbalancer.org appliance in AWS. It would replace the AWS NAT instance and give greater functionality and include both Layer4 and Layer7, along with SSL termination and a WAF.
Best of all you get free support in your 30 day trial in AWS to help you get up and running.
Yes I am biased as I work for loadbalancer.org however I would say nothing ventured nothing gained.
You can use a DNS service like DNSMadeeasy that allows "ANAME" records. These act like an A Record but can be pointed at a FQDN or IP. So in this case you can point it to the ELB DNS.
Dave