Mail Server customers now have the option to add External Address Verification (EAV), allowing IMail to be used as a gateway for an internal server. With the addition of EAV, message recipients can be verified as valid users before the message is accepted, eliminating unnecessary strain on both the gateway server and the internal server.

How It Works


External Address Verification is used by SMTP in the RCPT TO and VRFY commands. When one of these commands is received, it is first checked for a local host, then the address is passed to EAV where it is sent to several “verifiers” to determine if the message is valid or not. EAV also makes use of an in-memory cache to reduce the number of queries that must be made to the verifiers. Whenever a verifier returns a positive result for an address, that address is added to the cache for a configurable amount of time. The next time that EAV verifies that address, it will be found in the cache first and immediately return a positive result.

All settings for EAV can be easily accessed in the Console or the Web Administrator.

Users have the option to:

  • Enable/Disable
  • Enable for specific domains
  • Set the memory limit (in MB or %) for the memory cache
  • Configure an LDAP/Active Directory verifier

External Address Verification can be added to either IMail Server or IMail Premium at the unlimited user level only.