We are using Amazon Route53 for DNS management at Presslabs. Besides the actual
DNS Manager from the Presslabs Dashboard, we also use Amazon Route53 for automatic failover and geo serving of the content. Our open-source policy based records alternative for Amazon’s service is called Zinc, and we tell you all about it on our blog.
How does the DNS failover work?
All sites that are hosted with us have a chain of
Alias DNS Records that are configured together with
Health Checks in order to have a full DNS Failover service.
Practically, this means that whenever a server goes down for any reason, its corresponding health check will fail and Route53 will remove it from the pool of available servers. All these operations are automatic and take about 60 seconds to complete. Other servers are then taking over the traffic and serve your site.
First thing to know is that you can have multiple domains for a single site, and the list of domains can be managed in the Domains tab of the Presslabs Dashboard.
There are a few records in the DNS manager that you won’t be able to edit because they are managed by us. This is because without those records your site won’t work as expected, and we want to avoid downtimes because of this. These records are as following:
@-> this is the main A-record of your site and it’s usually the first record from the list. We’re using aliases in order to ensure our redundancy and failover
@, Type = NS -> these are the name servers for your site. In case you’re migrating from another host to Presslabs, please put these name servers in your DNS registrar, after you have the confirmation from a Presslabs engineer that your site is ready for name servers switch. They are also useful in case you want to change your DNS registrar.
wwwor other sub-domains -> in case you’ve added more sub-domains on the Domains tab, then all their corresponding records will be read-only.
Other DNS records
There are other DNS records that you’ll find in the DNS manager of the Presslabs dashboard and here’s a few of them that you’ll find:
@, Type = SPF -> these are the SPF (Sender Policy Framework) records and are used to validate that the e-mails sent from your domain are authentic and not spoofed. Please add here the corresponding SPF record for your e-mail service provider.
mandrill._domainkeys, Type = TXT -> this record is needed to send WordPress specific e-mails, like password reset e-mail, new comments notifications and all other WordPress specific e-mails
cdn, Type = CNAME -> this record can have other names depending on your preference and it’s automatically generated from the sub-domain you enter in the Domains tab. It should not be edited from here, but from the Settings page.