The DNS zone is the mapping between your domain name and the servers that host your website and your email. It is what you edit when you change server, add a subdomain or configure your email addresses.
Where your DNS zone is hosted
When a domain is registered with OpenVista, its zone is managed on OpenVista name servers: you edit it from your client area. If the domain is registered with another registrar, you can either manage the zone there or point its name servers to OpenVista. In the second case, wait for propagation before creating records, otherwise they will have no effect.
The essential record types
- A: maps a name to an IPv4 address. This is the record that publishes your website.
- AAAA: same role for an IPv6 address.
- CNAME: makes one name an alias of another name (for example
wwwto the main domain). Do not use it on the domain apex, nor alongside another record with the same name. - MX: identifies the server that receives mail; it carries a preference number.
- TXT: free text used for mail authentication (SPF), certificate validation or service verification.
Editing a record
In the zone, locate the name concerned and then create or edit the record. Check that the value does not end with a dot if it must be relative, and that only one A record points a given name to a given destination. For a new site the usual order is: A record to the server address, then update of the hostname in the hosting panel or vhost.
TTL and propagation
The TTL defines how long resolvers keep a record in cache, in seconds. A short value speeds up the effect of a change but generates more queries; a long value stabilises traffic but delays updates. Before a migration, lower the TTL, wait for the old delay, then change the value: this avoids a long outage.
Checking the configuration
From a terminal, query the public zone to confirm the registry answers with the new value:
dig +short A example.com dig +short MX example.com dig +short TXT example.com
Repeat the query against a public resolver: if the answer differs, the local or provider cache has not expired yet.
Common troubleshooting
- Site unreachable after a change: check the IP address on the server, then the local DNS cache.
- Mail rejected: check the MX record and the TXT record that authorises sending servers.
- Certificate refused: the requested validation record must be published exactly as supplied, without modification.
- Duplicates: two different A records on the same name produce random behaviour.
