Spf max time MTA option

SPF MTA options: (integer)
The  MTA option specifies  the maximum amount of time, in seconds, permitted when performing an SPF check. If an SPF check does not complete in this amount of time, an SPF TempError will be returned. The default is 45. (RFC 4408 (SPF) in Section 10.1 recommends allowing at least 20 seconds.)

See also:
 * SPF MTA options