Submission SMTP Send Connector Test

The Mailbox Transport Submission service connects to the local mailbox database using RPC to retrieve messages, and submits the messages over SMTP to the Transport service on the local Mailbox server, or on other Mailbox servers. To select the best Transport service (which could be local or on another server) to submit the messages to and to actually forward the messages to the Default Receive Connector on the chosen Transport Service, the Mailbox Transport Submission services relies on Send Connectors. If one/more of these send connectors fail due to errors or operate at a lethargic pace, it is bound to severely impact the selection and submission of emails to the Transport service. If ignored, this will aggravate and adversely impact the timely delivery of mails to the destination mailboxes. To prevent this, administrators should monitor each SMTP send connector used the Mailbox Submission Service and proactively identify those send connectors that are either latent or error-prone. The Submission SMTP Send Connector test helps administrators achieve this. This test monitors every send connector used by the Mailbox Transport Submission service and reports the throughput of and errors encountered by each send connector. This way, the test accurately pinpoints send connectors that could be experiencing processing bottlenecks and the ones that are error-prone.

Target of the test : A Microsoft Exchange 2013/2016 server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for each submission send connector

Configurable parameters for the test
  1. Test period - How often should the test be executed
  2. Host - The host for which the test is to be configured.
  3. port – The port at which the host listens.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Data sent rate:

Indicates the rate at which this send connector sends data.

KB/Sec

A consistent drop in the value of this measure could indicate a bottleneck when submitting messages. Compare the value of this measure across send connectors to know which connector is slowing down mail submission.

Outbound connections from send connector:

Indicates the number of outbound connections from this SMTP send connector.

Number

Compare the value of this measure across connectors to identify the busiest connector.

Messages sent by send connector:

Indicates the rate at which messages are sent by this send connector.

Msgs/Sec

A consistent decrease in the value of this measure is indicative of a slowdown when submitting messages. To know which send connector is the slowest, compare the value of this measure across connectors.

Connection failures encountered by connector:

Indicates the number of connection failures encountered by this send connector.

Number

Ideally, the value of this measure should be 0. A high value indicates serious connection problems, which need to be investigated right away. Compare the value of this measure across connectors to identify the connector with the maximum connection failures.

DNS errors encountered by connector:

Indicates the number of DNS errors encountered by this send connector.

Number

Ideally, the value of this measure should be 0. A high value indicates serious issues in name space resolution, which need to be investigated right away. Compare the value of this measure across connectors to identify the connector with the maximum number of DNS errors.

Protocol errors encountered by connector:

Indicates the number of protocol errors encountered by this send connector.

Number

Ideally, the value of this measure should be 0. A high value indicates serious protocol issues, which need to be investigated right away. Compare the value of this measure across connectors to identify the connector with the maximum number of protocol errors.

Socket errors encountered by connector:

Indicates the number of socket errors encountered by this send connector.

Number

Ideally, the value of this measure should be 0. A high value indicates serious socket issues, which need to be investigated right away. Compare the value of this measure across connectors to identify the connector with the maximum number of socket errors.