Configuring the Internal DNS Table

The Internal DNS table, similar to a DNS resolution can translate up to 20 host (domain) names into IP addresses. This functionality can be used when a domain name (FQDN) is configured as an IP destination in a routing rule. For the Gateway application, this is typically used for alternative Tel-to-IP call routing. Up to three different IP addresses can be assigned to the same host name.

The device attempts to resolve a domain name into an IP address in the following order:

The device first checks the Internal DNS table for a matching domain name and if found, resolves the domain name into the corresponding IP address(es).

If no matching domain name exists in the Internal DNS table, the device performs a DNS query with an external third-party DNS server whose address is configured for the associated IP network interface in the IP Interfaces table (see Configuring IP Network Interfaces).

The device uses the Internal DNS table only for call routing, for example:

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Call routing according to a SIP Request-URI that contains a hostname.

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Call routing by destination address that is configured as a hostname.

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Call routing by ENUM and the result of the ENUM query is a hostname.

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DNS resolution of proxy servers in a Proxy Set that are configured with an FQDN.

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Registering a user agent whose REGISTER message has a Contact header that is a hostname.

The following procedure describes how to configure the DNS table through the Web interface. You can also configure it through ini file [DNS2IP] or CLI (configure network > dns dns-to-ip).

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To configure the device's DNS table:

Open the Internal DNS table (Setup menu > IP Network tab > DNS folder > Internal DNS).

Click New; the following dialog box appears:

Configure a DNS rule according to the parameters described in the table below.

Click Apply.

Internal DNS Table Parameter Description

Parameter	Description
'Index'	Defines an index number for the new table row. Note: Each row must be configured with a unique index.
'Domain Name' domain-name [Dns2Ip_DomainName]	Defines the host name to be translated. The valid value is a string of up to 31 characters.
'First IP Address' first-ip-address [Dns2Ip_FirstIpAddress]	Defines the first IP address (in dotted-decimal format notation) to which the host name is translated. The IP address can be configured as an IPv4 and/or IPv6 address.
'Second IP Address' second-ip-address [Dns2Ip_SecondIpAddress]	Defines the second IP address (in dotted-decimal format notation) to which the host name is translated.
'Third IP Address' third-ip-address [Dns2Ip_ThirdIpAddress]	Defines the third IP address (in dotted-decimal format notation) to which the host name is translated.