Working with Multiple Domains

You can use a wildcard (*) with the HNT feature to accommodate multiple domains and to allow the Oracle® Enterprise Session Border Controller to cache all HNT endpoints. The wildcard functionality is enabled in the SIP config by entering an asterisk (*) in the registrar domain and registrar host fields.

The wildcard allows the use of either a local policy or Domain Name Service (DNS) to resolve the domain name to the correct registrar. Either method can be used to route the Fully Qualified Domain Name (FQDN) when the you enter an asterisk (*) for the register host. An FQDN consists of an unlimited number of domain labels (domain names), each separated by a dot (.). The FQDN can include the top level domain name (for example, acmepacket.com).

In the hostname acme-packet.domainlbl.example100.com, the syntax is as follows:

• acme-packet is a domain label
• domainlbl is a domain label
• example100 is a domain label
• com is the top label

The information configured in a local policy is used before DNS is used. If the next hop destination address (defined in the local policy’s next hop field) is an IPv4 address, a DNS server is not needed. A DNS server is needed when the IPv4 address of the next hop destination address is a FQDN or cannot be determined from the Oracle® Enterprise Session Border Controller’s configuration. Even with a configured local policy, the next hop destination address might be an FQDN that requires a DNS lookup.

If the registrar host does not use the wildcard, the Oracle® Enterprise Session Border Controller always uses the configured address. You can limit the number of endpoints that receive the HNT function. For example, you can use a non-wildcarded registrar domain field value (like acme.com) with a wildcarded registrar host field value.