SMTP is a communication protocol for electronic mail transmission.

### SMTP Port

- IPv4 Ports: SMTP port for IP version 4.
- IPv4 Secure Ports: Implicit SSL SMTP port for IP version 4.
- IPv4 TLS Ports: Explicit SSL SMTP port for IP version 4.
- IPv6 Ports: SMTP port for IP version 6.
- IPv6 Secure Ports: Implicit SSL SMTP port for IP version 6.
- IPv6 TLS Ports: Explicit SSL SMTP port for IP version 6.

### Service Time

Mode: To apply service time for SMTP response.

1. No Service Time: No service time delay is applied. Helps in doing max load testing.
   - value1: Not Applicable.
   - value2: Not Applicable
   - Description: Helps in doing max load testing
2. Exponential Random: Exponential random service time with median of specified seconds is applied. For exponential random distribution, median is roughly around 1/4th of the mean. This takes a random value equivalent to median time.
   - value1: Median Time(> 0)
   - value2: Not Applicable
   - Description: This takes a random value equivalent to median time.
3. Constant: A constant service time of specified seconds. Helps in doing controlled tests
   - value1: Constant Time (> 0)
   - value2: Not Applicable
   - Description:Helps in doing controlled tests. It takes a constant value. As one can calculate the number of page requests expected within certain duration.
4. Uniform Distribution: It is more Realistic. The value is a random value between the minimum and maximum time defined. Min should be less than or equal to Max.
   - value1: Minimum Time (>= 0)
   - value2: Maximum Time(> 0 and >= Min)
   - Description: It is more Realistic. The value is a random value between the minimum and maximum time defined. Min should be less than or equal to Max.

### Command:

- GREETING: Used for session initiation.
- HELO: Starts the conversation identifying the sender server and is generally followed by its domain name.
- EHLO: An alternative command to start the conversation, underlying that the server is using the Extended SMTP protocol.
- AUTH: To authenticate the client to the server.
- USERNAME: Authentication User name
- PASSWORD: Authentication Password
- MAIL: To establish the return address.
- RCPT: To establish a recipient of the message.
- DATA: The email content begins to be transferred; it’s generally followed by a 354 reply code given by the server, giving the permission to start the actual transmission.
- VRFY: The server is asked to verify whether a particular email address or username actually exists.
- EXPN: Asks for a confirmation about the identification of a mailing list.
- RSET: Communicates to the server that the ongoing email transmission is going to be terminated, though the SMTP conversation won’t be closed (like in the case of QUIT).
- NOOP: Used only to check whether the server can respond. “250 OK” reply in response.
- QUIT: Terminates the SMTP conversation.
- HELP: A client’s request for some information that can be useful for a successful transfer of the email.
- ALL: To apply service time for all of the commands, choose ALL.

Average Time: The Time taken in between Min and Max time (Formula: (Min+Max)/2) or (no of transactions * time of each transaction / total no of transactions).

Maximum Time: Time taken for completing the Service test.

### Authentication

Mode: To support authentication mechanism for SMTP.

- Do Not Enable Auth Login: Do not enable authentication login.
- Enable Auth Login But Do Not Check Validity Of User Name/Password: Enable authentication login but do not check validity of username and password.
- Enable Auth Login And Check Validity Of User Name/Password: Enable authentication login and check the validity of username and password.

### Error Simulation

- Command
  - GREETING: Used for session initiation.
  - HELO: Starts the conversation identifying the sender server and is generally followed by its domain name.
  - EHLO: An alternative command to start the conversation, underlying that the server is using the Extended SMTP protocol.
  - AUTH: To authenticate the client to the server.
  - USERNAME: Authentication User name
  - PASSWORD: Authentication Password
  - MAIL: To establish the return address.
  - RCPT: To establish a recipient of the message.
  - DATA: The email content begins to be transferred; it’s generally followed by a 354 reply code given by the server, giving the permission to start the actual transmission.
  - VRFY: The server is asked to verify whether a particular email address or username actually exists.
  - EXPN: Asks for a confirmation about the identification of a mailing list.
  - RSET: Communicates to the server that the ongoing email transmission is going to be terminated, though the SMTP conversation won’t be closed (like in the case of QUIT).
  - NOOP: Used only to check whether the server can respond. “250 OK” reply in response.
  - QUIT: Terminates the SMTP conversation.
  - HELP: A client’s request for some information that can be useful for a successful transfer of the email.
- ALL: To apply service time for all of the commands, choose ALL.
- Percentage: Value in percent for which user wants the user defined response in case of error simulation.
- Response: User defined response in case of Error simulation.