element: <InterEnumTime>

Value: positive integer

The <InterEnumTime> element controls the delay between enumerations. If set to zero, then address enumeration will not occur.

For verifiers with periodic enumeration, all email addresses are retrieved from one of the verification servers and stored in a cache of valid email addresses. This enumeration is performed simultaneously from many servers in the case of a Communigate verifier, or from each sub-verifier in a Multi verifier . This cache allows the application to respond instantly to verification requests.

Although this address enumeration places considerable load on the verification servers, it can shield servers from the severe load of a Directory Harvest Attacks (DHA). You can expect enumeration of large LDAP servers to take up to ten minutes. If the enumeration procedure encounters an error, the entire database of enumerated email addresses is immediately discarded.

The following table summarizes the default <InterEnumTime> values for each verifier type. Note that when defining a Multi verifier, the <InterEnumTime> element is not allowed within a sub-verifier, and the default <InterEnumTime> is zero (disabled).

To enumerate a Multi verifier, you must explicitly request automatic enumeration by placing an <InterEnumTime> element as a child of the <Multi> parent element. Enumeration of all sub-verifiers of a Multi verifier is initiated in parallel.