This section contains the registry path for Microsoft SMTP Service and an alphabetical list of service-specific registry entries.
Global registry entries and all other service-specific entries are documented in Registry in the AdministratorÆs Reference in the IIS documentation.
Note For a registry change to take effect, you must restart the service.
HKEY_LOCAL_MACHINE
\SYSTEM
\CurrentControlSet
\Services
\SmtpSvc
\Parameters
Microsoft SMTP Service maintains the registry entries listed below.
| DirectoryBuffSize |
| Datatype: REG_DWORD |
| Default: 1000 |
| This value sets a limit on the size of the memory buffer that is used to store messages from the Pickup directory during processing. |
| DnsSocketTimeout |
| Datatype: REG_DWORD |
| Default: 60,000 (milliseconds) |
| This value sets a limit on the amount of time Microsoft SMTP Service will wait for a response from the domain name server. After this interval, the connection is dropped and the message is put in the retry queue. |
| MaxAddressObjects |
| Datatype: REG_DWORD |
| Default: 100,000 |
| This value sets a limit on the number of address objects. Address objects are used by Windows NT to represent addresses in memory. |
| MaxDirectoryBuffers |
| Datatype: REG_DWORD |
| Default: 2000 |
| This value sets a limit on the number of buffers that are used to store messages from the Pickup directory during processing. |
| MaxMailObjects |
| Datatype: REG_DWORD |
| Default: 100,000 |
| This value sets a limit on the number of mail objects. Mail objects are used by Windows NT to represent messages in memory. |
| NumDnsResolverSockets |
| Datatype: REG_DWORD |
| Default: 10 |
| This value sets the number of sockets Microsoft SMTP Service opens to a domain name server. |