External Address Verification

External Address Verification (available and sold separately) allows IMail Administrators capability to use the IMail Server as a gateway to determine valid users on the destination server and reject all other recipients as invalid at the gateway.

This user verification process can be made by setting up an External Address Verifier. The External Address Verifier simply identifies users as valid or invalid.

The External Address Verifier is highly configurable, but currently only LDAP is supported as a verification database.

External Address Verification

Note: Restart SMTP Services after modifications are made to External Address Verifiers.

System Setting to Enable External Address Verification
- Verification Disabled. (Set by default) Globally disabled all External Address Verification.
- Verification Enabled. Enables Address verification as defined by the Verification List.
- Enabled for Specified Domains. This setting will process address verification for only specified domains.
  Note: Domains that are not on this list, will bypass all External Address Verifications and process as usual.

Enabled for Specified Domains

Domain Name. This list is available only when Enabled for Specified Domain Names is set. This list identifies domains that use External Address Verification.
Wildcard capability is available. See Examples.

Note: Domain Names list will only display when "Enabled for Specified Domains" is selected

Verifiers

Verifier Name. Enter a name in the text box to identify the Verifier. This can be any name that you want, and will be used in log lines to identify the External Address Verification entry.
Verifier Type. Select the type of lookup that the Verifier performs.
Verifier Enabled. (True by Default) Displays the verifiers that are active. Click "Edit" to disable a verifier temporarily.
Note: Use "Delete" to permanently remove a verifier.

Add. Click to create a new verifier.

Delete. Click to permanently remove a verifier.

To modify the order of verification, select a verifier and click one of the following buttons

Move Up. Moves selected verifier up one line.
Move Down. Moves selected verifier down one line.
Move To Top. Moves selected verifier to the top of the list.
Move To Bottom. Moves selected verifier to the bottom of the list.

Advanced Settings

Tip: Restarting SMTP will clear all addresses in cache.

Caching Enabled. (Not set by Default) The verification process is considered an expensive cpu resource, and with a busy mail server this could at times backup the mail process. Activating Verification Caching will allow storage of verified addresses and bypass the expensive duplicate address lookups. Verified addresses will only remain in cache for the duration of the Entry Timeout Interval setting (this setting is reset each time a match is made in cache). If the cache settings for Memory Limits are left at their default zero settings then the operating system will calculate settings based on system experience and history, which usually is unlimited.
Note: It is recommended that IMail Administrators set their Memory Limits and tweak as necessary to attain the best server efficiency.
- Memory Limit (MB). (Default = 0) Maximum amount of memory allowed for caching. Once this maximum space is met, the oldest cache listings will be dropped. The default setting of zero allows the operating system to determine the limit, which effectively is unlimited.
- Memory Limit (%). (Default = 0) Maximum percentage of memory allowed for caching. Once this percentage is met, the oldest cache listings will be dropped.
- Entry Timeout Interval (minutes). (Default = 240) Length of time that an entry will remain in cache before being cleared out.
  Note: Each time a cached entry is verified the Entry Timeout Interval is reset.
- Polling Interval (minutes). (Default = 2) The time interval set for cache to be poll itself. The polling process includes cleaning out expired address and also removes entries necessary to keep the memory limits within settings.
  Note: Polling is an expensive process, it is recommended not to change the default setting.

Add. Click this button to Add to External Address Verifier page.
Delete. Select an item to delete and click the Delete button.

Warning: Updates made to the External Address Verification list will not successfully update until the "Save" button has been clicked, and the message "Your changes have been saved" is displayed at the top.

Save. Click to save your settings.

Add / Edit External Address Verifier

About External Address Verification