There may be times when troubleshooting a workflow which requires sending email, to determine that an SMTP server is available and responsive. The following can be used to confirm this, if telnet is available. This test connects to the external SMTP server and sends a message. Note that this only works for sending unencrypted email.
Below is a generic example of what you would attempt to send and then in (parenthesis) is some information and what you would typically use locally. Case doesn't appear to affect functionality in these tests.
C: is the client input - what you will be typing
S: is the server response - info that you should receive back
C: telnet host 25
S: 250 smtp.domainname.com Hello [10.10.10.1] (250 server01.company.com Hello [10.10.3.152] - Indicates that everything is ok so far)
S: 250 2.1.0 email@example.com....SenderOK (Indicates that so far everything is good)
S: 250 2.1.5 firstname.lastname@example.org (Indicates that so far everything is good)
S: 354 Start mail input. (Indicates that you may start writing the text that will go in the body of the email)
S: 250 Mail queued for delivery. (This indicates that we were successful)
Article # 3016870