Pointing DNS records to your public IP addresses

Although your website is hosted on a high-availability hosting cluster of several web servers, your website has a single public IP address. This address points to a load balancer that detects incoming connections to your website and spreads them among the cluster of web servers.

For your website to be available on the Internet, incoming connections must go to the Acquia Cloud load balancer. You can enable this through your DNS provider by pointing your domain name's A Records entry to the public IP address. In your DNS provider's web interface, change the A Records entry for your domain name to point to the public IP address, which is listed on the Acquia Cloud Domain page at Cloud > Domains. For example, suppose your website's domain name is www.example.com and your public IP address is 123.123.123.123. Set the A Records entry for www.example.com to 123.123.123.123.

Your site's IP address

Do not set your domain name's CNAME entry to an acquia-sites.com domain. Doing so can make your website load more slowly, and can cause unpredictable results or even downtime, especially if configuration changes are being made or tested to the load balancers. In addition, DNS service is not included in Acquia's uptime guarantee. This means that if the Acquia DNS provider has an outage, requests to *.prod.acquia-sites.com would fail to resolve, and any domains that are pointed to the Acquia domain (rather than to a public IP address or an Elastic Load Balancer) would fail.

DNS settings with an Elastic Load Balancer

If you have an Elastic Load Balancer (ELB) for your website (which would be the case if you have enabled HTTPS for your website), instead of changing the A Records entry, change the CNAME entry for your domain name. In your DNS provider's web interface, change the CNAME entry for your domain name to point to the URL of your Acquia Cloud environment, which will be the URL of your Elastic Load Balancer and which is listed on your Acquia Cloud Domain page at Cloud > Domains. Don't use a DNS A Record to point to the underlying IP address of the ELB, since the IP address may change from time to time.

URL of the ELB

For example, suppose your website's domain name is www.example.com and your Prod environment's URL is ab-1234-us-east-1.elb.amazonaws.com. Set the CNAME entry for www.example.com to ab-1234-us-east-1.elb.amazonaws.com.

Note: The URL of your Acquia Cloud environment may be long. Check with your DNS provider to ensure that they can handle a CNAME for a URL of that length.

Using an Elastic IP address

An Acquia Cloud website can use an Elastic IP Address (EIPs) in order to have a static IP address assigned to its server instance. Without an Elastic IP, your instances' IP addresses are subject to change at any time as the underlying hardware is relaunched or replaced. For most purposes, that doesn't make a difference for Acquia Cloud websites. However, you might want to use EIPs if it is important to you to maintain the same IP address, for example, so that you can add them to a whitelist, integrate them with a Single-Sign-On (SSO) solution, or with a third-party service that requires a static IP address.

An EIP persists when a server is relaunched or rebooted. It will be lost if a server is suspended, for example after being removed due to a downsize.

Using EIPs can reduce your flexibility if you need additional server capacity to meet increased website traffic. While the Acquia Operations team can quickly provision new instances for your website in response to demand, the additional instances can't be brought into service until the new EIPs associated with them can be added to your whitelist or other system.

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