SMTP Sensor

SMTP (Short for Simple Mail Transfer Protocol) is the basic protocol for sending e-mail messages between mail servers over the Internet. Whenever you send or receive an e-mail it is transferred using this protocol.

The SMTP sensor of IPCheck Server Monitor supports monitoring on three levels:

·      HELO: The SMTP server is contacted and a few bytes of communication are transferred according to the protocol definition and then cancels the connection. This ensures that the server is accepting requests and answers according to the protocol.

·      RCPT: Additionally IPCheck Server Monitor tries to begin delivering an email to a given email address and then cancels the connection. This checks whether the email server actually accepts mails to this address at all.

·      DATA: Additionally IPCheck Server Monitor sends a complete email to a given email address and finishes the communication. This most thoroughly checks if the mail server accepts and processes the email but on the other hand the recipient will get an email with each check (!), so this should only be used for debugging purposes.

Parameters include:

·      PORT—the port number of the mail service you want to monitor (usually port 25)

·      Monitoring Level—The level of monitoring (see above)

·      Helo Ident—For some mail servers the HELO ident must be the valid principal host domain name for the client host (i.e. the machine running IPCheck Server Monitor)

·      From—Sender ('From:' part) of the mail

·      To—Recipient(s) ('To:' part) of the mail

·      Topic—'Subject:' part of the mail

·      Content—Body of the mail

More:

What it means when the SMTP Sensor is up

What it means when the SMTP Sensor sensor is down