Queries are sent to Domain Name System (DNS) servers that Secure Web Gateway connects for retrieving the IP addresses that match the host names submitted in user requests.
Using DNS servers according to domains
The use of DNS (Domain Name System) servers to resolve domain information provided in URLs into IP addresses when requests for web access are processed on Secure Web Gateway can be configured according to the domains of the requested destinations.
This use of DNS servers is also known as conditional DNS forwarding.
Domains, for example, testnet.webwasher.com, are entered into a list together with the IP address of the DNS server that is used to resolve the URL information. More than one DNS server can be specified this way for a domain.
When a request to a particular destination on the web is sent to Secure Web Gateway, it is forwarded to a DNS server according to this list.
The use of a particular DNS server can be configured dynamically with DHCP (Dynamic Host Configuration Protocol. This is also the default setting after the initial setup of a Secure Web Gateway appliance.
If both configuration with DHCP and conditional DNS forwarding are configured, DHCP takes precedence and conditional DNS forwarding is bypassed.
NOTE: If a BIND server is configured as a DNS server, the DNS server settings that are stored in a configuration file on Secure Web Gateway will be overwritten. To keep these settings for domain name resolving, you need to enter them manually again.
Configure DNS servers according to domains
To enable the use of DNS servers according to the domains of destinations in the web, configure the Domain Name Service settings in a suitable manner.
- Select Configuration | Appliances.
- On the appliances tree, select the appliance you want to configure the use of DNS servers for and click Domain Name Service.
- Configure the settings in the Conditional DNS Forwarder Configuration section as needed.
- Click Save Changes.