isResolvable()(host)

If the DNS inside the firewall recognizes only internal hosts, you can use the isResolvable()() function to test whether a host name is internal or external to the network. Using this function, you can configure the browser to use direct connections to internal servers and to use the proxy only for external servers. This function is useful at sites where the internal hosts inside the firewall are able to resolve the DNS domain name of other internal hosts, but all external hosts are unresolvable. The isResolvable()() function consults DNS, attempting to resolve the host name into an IP address. See Example 3: Proxy Only Unresolved Hosts

Parameters

host() is the host name from the URL.

Return Values

true if the function can resolve the host name, false if it cannot

Example

isResolvable("host")

If host() is a string like www and can be resolved through DNS, then this function returns true.