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Merge pull request #355 from open-guides/copy-edits

Copy edits on #347.
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Joshua Levy 2016-12-13 15:19:44 -08:00 committed by GitHub
commit c8ae1290d7

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@ -1004,7 +1004,7 @@ CLB
- **Apex DNS names:** Once upon a time, you couldnt assign an CLB to an apex DNS record (i.e. example.com instead of foo.example.com) because it needed to be an A record instead of a CNAME. This is now possible with a Route 53 alias record directly pointing to the load balancer. - **Apex DNS names:** Once upon a time, you couldnt assign an CLB to an apex DNS record (i.e. example.com instead of foo.example.com) because it needed to be an A record instead of a CNAME. This is now possible with a Route 53 alias record directly pointing to the load balancer.
- 🔸CLBs use [HTTP keep-alives](https://en.wikipedia.org/wiki/HTTP_persistent_connection) on the internal side. This can cause an unexpected side effect: Requests from different clients, each in their own TCP connection on the external side, can end up on the same TCP connection on the internal side. Never assume that multiple requests on the same TCP connection are from the same client! - 🔸CLBs use [HTTP keep-alives](https://en.wikipedia.org/wiki/HTTP_persistent_connection) on the internal side. This can cause an unexpected side effect: Requests from different clients, each in their own TCP connection on the external side, can end up on the same TCP connection on the internal side. Never assume that multiple requests on the same TCP connection are from the same client!
- 🔸 Traffic between CLBs and back-end instances in the same subnet **will** have [Network ACL](http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_ACLs.html) rules evaluated (EC2 to EC2 traffic in the same subnet would not have Network ACL rules evaluated). If the default '0.0.0.0/0 ALLOW' rule is removed from the Network ACL applied to the subnet, a rule that allows traffic on both the health check port and any listener port must be added. - 🔸 Traffic between CLBs and back-end instances in the same subnet **will** have [Network ACL](http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_ACLs.html) rules evaluated (EC2 to EC2 traffic in the same subnet would not have Network ACL rules evaluated). If the default '0.0.0.0/0 ALLOW' rule is removed from the Network ACL applied to the subnet, a rule that allows traffic on both the health check port and any listener port must be added.
- As of December 2016, CLBs launched in VPCs do not support IPv6 addressing. CLBs launched in EC2-Classic support both IPv4 and IPv6 [with the "dualstack" DNS name.](http://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-internet-facing-load-balancers.html#internet-facing-ip-addresses) - As of December 2016, CLBs launched in VPCs do not support IPv6 addressing. CLBs launched in EC2-Classic support both IPv4 and IPv6 [with the "dualstack" DNS name](http://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-internet-facing-load-balancers.html#internet-facing-ip-addresses).
ALB ALB
--- ---
@ -1029,7 +1029,7 @@ ALB
- Instances in the ALBs target groups have to either have a single, fixed healthcheck port (“EC2 instance”-level healthcheck) or the healthcheck port for a target has to be the same as its application port (“Application instance”-level healthcheck) - you can't configure a per-target healthcheck port that is different than the application port. - Instances in the ALBs target groups have to either have a single, fixed healthcheck port (“EC2 instance”-level healthcheck) or the healthcheck port for a target has to be the same as its application port (“Application instance”-level healthcheck) - you can't configure a per-target healthcheck port that is different than the application port.
- ALBs are VPC-only (they are not available in EC2 Classic) - ALBs are VPC-only (they are not available in EC2 Classic)
- In a target group, if there is no healthy target, all requests are routed to all targets. For example, if you point a listener at a target group containing a single service that has a long initialization phase (during which the health checks would fail), requests will reach the service while it is still starting up. - In a target group, if there is no healthy target, all requests are routed to all targets. For example, if you point a listener at a target group containing a single service that has a long initialization phase (during which the health checks would fail), requests will reach the service while it is still starting up.
- Although it has been announced as coming soon, [ALBs do not presently support IPv6.](https://aws.amazon.com/about-aws/whats-new/2016/12/announcing-internet-protocol-version-6-support-for-ec2-instances-in-amazon-virtual-private-cloud/) Even if the ALB is launched in an IPv6-enabled VPC and subnet, it will only have IPv4 addressing. - As of December 2016, although it has been announced as coming soon, ALBs [do not yet support IPv6](https://aws.amazon.com/about-aws/whats-new/2016/12/announcing-internet-protocol-version-6-support-for-ec2-instances-in-amazon-virtual-private-cloud/). Even if the ALB is launched in an IPv6-enabled VPC and subnet, it will only have IPv4 addressing.
Elastic IPs Elastic IPs
----------- -----------
@ -1368,7 +1368,7 @@ VPCs, Network Security, and Security Groups
- **VPC Flow Logs** allow you to monitor the network traffic to, from, and within your VPC. Logs are stored in CloudWatch Logs groups, and can be used for security monitoring (with third party tools), performance evaluation, and forensic investigation. - **VPC Flow Logs** allow you to monitor the network traffic to, from, and within your VPC. Logs are stored in CloudWatch Logs groups, and can be used for security monitoring (with third party tools), performance evaluation, and forensic investigation.
- See the [VPC Flow Logs User Guide](http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/flow-logs.html) for basic information. - See the [VPC Flow Logs User Guide](http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/flow-logs.html) for basic information.
- See the [flowlogs-reader](https://github.com/obsrvbl/flowlogs-reader) CLI tool and Python library to retrieve and work with VPC Flow Logs. - See the [flowlogs-reader](https://github.com/obsrvbl/flowlogs-reader) CLI tool and Python library to retrieve and work with VPC Flow Logs.
- **IPv6** [is available in VPC.](https://aws.amazon.com/blogs/aws/new-ipv6-support-for-ec2-instances-in-virtual-private-clouds/) Along with this announcement came the introduction of the Egress-Only Internet Gateway. In cases where one would use NAT Gateways to enable egress-only traffic for their VPC in IPv4, one can use an Egress-Only Internet Gateway for the same purpose in IPv6. - **IPv6** [is available in VPC](https://aws.amazon.com/blogs/aws/new-ipv6-support-for-ec2-instances-in-virtual-private-clouds/). Along with this announcement came the introduction of the [Egress-Only Internet Gateway](https://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/egress-only-internet-gateway.html). In cases where one would use NAT Gateways to enable egress-only traffic for their VPC in IPv4, one can use an Egress-Only Internet Gateway for the same purpose in IPv6.
- Amazon provides an IPv6 CIDR block for your VPC at your request - at present you cannot implement your own IPv6 block if you happen to own one already. - Amazon provides an IPv6 CIDR block for your VPC at your request - at present you cannot implement your own IPv6 block if you happen to own one already.
- New and existing VPCs can both use IPv6. Existing VPCs will need to be configured to have an IPv6 CIDR block associated with them, just as new VPCs do. - New and existing VPCs can both use IPv6. Existing VPCs will need to be configured to have an IPv6 CIDR block associated with them, just as new VPCs do.
@ -1423,7 +1423,7 @@ CloudFront
### CloudFront Tips ### CloudFront Tips
- 🐥**IPv6** is [supported](https://aws.amazon.com/about-aws/whats-new/2016/10/ipv6-support-for-cloudfront-waf-and-s3-transfer-acceleration/). This is a configurable setting, and is enabled by default on new CloudFront distribution. IPv6 support extends to the use of WAF with CloudFront. - 🐥**IPv6** is [supported](https://aws.amazon.com/about-aws/whats-new/2016/10/ipv6-support-for-cloudfront-waf-and-s3-transfer-acceleration/). This is a configurable setting, and is enabled by default on new CloudFront distributions. IPv6 support extends to the use of WAF with CloudFront.
- 🐥**HTTP/2** is [now supported](https://aws.amazon.com/about-aws/whats-new/2016/09/amazon-cloudfront-now-supports-http2/)! Clients [must support TLS 1.2 and SNI](https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-web-values-specify.html#DownloadDistValuesSupportedHTTPVersions). - 🐥**HTTP/2** is [now supported](https://aws.amazon.com/about-aws/whats-new/2016/09/amazon-cloudfront-now-supports-http2/)! Clients [must support TLS 1.2 and SNI](https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-web-values-specify.html#DownloadDistValuesSupportedHTTPVersions).
- While the most common use is for users to browse and download content (GET or HEAD methods) requests, CloudFront also supports ([since 2013](https://aws.amazon.com/blogs/aws/amazon-cloudfront-content-uploads-post-put-other-methods/)) uploaded data (POST, PUT, DELETE, OPTIONS, and PATCH). - While the most common use is for users to browse and download content (GET or HEAD methods) requests, CloudFront also supports ([since 2013](https://aws.amazon.com/blogs/aws/amazon-cloudfront-content-uploads-post-put-other-methods/)) uploaded data (POST, PUT, DELETE, OPTIONS, and PATCH).
- You must enable this by specifying the [allowed HTTP methods](https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-web-values-specify.html#DownloadDistValuesAllowedHTTPMethods) when you create the distribution. - You must enable this by specifying the [allowed HTTP methods](https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/distribution-web-values-specify.html#DownloadDistValuesAllowedHTTPMethods) when you create the distribution.
@ -1686,7 +1686,7 @@ WAF
- WAF (Web Application Firewall) is used in conjunction with the CloudFront and ALB services to inspect and block/allow web requests based on user-configurable conditions. - WAF (Web Application Firewall) is used in conjunction with the CloudFront and ALB services to inspect and block/allow web requests based on user-configurable conditions.
- HTTPS and HTTP requests are supported with this service. - HTTPS and HTTP requests are supported with this service.
- WAF's strength is in detecting malicious activity based on pattern-matching inputs for attacks such as SQL injections, XSS, etc. - WAF's strength is in detecting malicious activity based on pattern-matching inputs for attacks such as SQL injections, XSS, etc.
- WAF supports inspection of requests [received through both IPv6 and IPv4.](https://aws.amazon.com/about-aws/whats-new/2016/10/ipv6-support-for-cloudfront-waf-and-s3-transfer-acceleration/) - WAF supports inspection of requests [received through both IPv6 and IPv4](https://aws.amazon.com/about-aws/whats-new/2016/10/ipv6-support-for-cloudfront-waf-and-s3-transfer-acceleration/).
### WAF Tips ### WAF Tips