Resource records contain service information about a domain zone. IPmanager manages PTR, SOA, and NS.
PTR-record
A PTR-record is used to map IP addresses to domain names. This record is mostly used to track where an e-mail message originated. Most mail servers check that a PTR-record exists and matches the domain name that the email was sent from. If the verification fails, the email is considered spam, therefore is the PTR-record is not present, emails from that IP may be blocked.
SOA-record
A SOA-record determines:
- Primary Name Server — primary DNS server of the domain zone (master);
- Hostmaster — email of the address responsible for administration of the domain zone;
- Serial number — serial number of the domain zone. It can be changed when the domain zone is updated. This number is used by DNS servers (slave) to check whether it's required to update the zones;
- Refresh — time period after which the system checks whether it needs to update a domain zone in seconds for secondary DNS servers. If the serial number has changed since its last check, then the domain zone on the secondary DNS server will be updated;
- Retry — time period after which the system tries again to check whether it needs to update a domain zone. It is only used if the first attempt the primary DNS server was unavailable;
- Expire — time period after the failed update of the domain zone, after which the secondary DNS server will cease to process requests about a domain zone;
- Minimum TTL — minimal lifetime of resource records of the domain zone. It is used as a time period during which the system can store data about the domain zone in the cache.
NS-record
NS-record is a domain name of the proxy server of the specified domain. It can and oftentimes must contain a few servers including the one specified in SOA.