On our new dual processor server more and more connections fail after a short time of higher SMTP traffic.
This may result from too many TCP sockets remaining in a TIME_WAIT state during mail delivery.
You can create two new REG_DWORD values under:
You can set TcpTimedWaitDelay (which has a default setting of 240 seconds) to cause TIME_WAIT sockets to clear more quickly.
For example, you can create the TcpTimedWaitDelay value and set it to 60 (seconds). The possible range for this value is from 30 to 300 seconds.
You can set MaxUserPort (which has a default setting of 5000) to allocate more outbound (client) sockets.
For example, you can create the MaxUserPort value and set it to 25000. The possible range for this valuse is from 5000 to 65534 ports.
A customer found that, after creating these values, he no longer saw "MX connect failed" or "status=3" in his logfiles. All messages were delivered immediately.