E-mail Protocol Diagnostics

The following telnet mocks can be used to test/diagnose email systems.

These commands will NOT be encrypted, or work on systems requiring TLS. Ensure any credentials used are changed/removed after testing, or are run exclusively on same machine as the mail server.

IMAP

Listing an IMAP mailbox

$ telnet SERVER 143
* OK [CAPABILITY IMAP4rev1 STARTTLS AUTH=PLAIN AUTH=LOGIN] Ready.

01 LOGIN [email protected] password
02 LIST "" *

POP3

Listing a POP3 mailbox

$ telnet SERVER 110
+OK POP3 perditon ready on mail.example.com

USER [email protected]
+OK USER [email protected] set, mate

PASS password
+OK You are so in

LIST
+OK 0 messages:

SMTP

Sending a message via SMTP — Unauthenticated

$ telnet SERVER 25
-> 220

HELO sending-host-fqdn.example.com
-> 250

MAIL FROM: [email protected]
-> 250

RCPT TO: [email protected]
-> 250

DATA
Your message here, and continues
until sending a line containing
only a single period (full-stop).
.
-> 250

QUIT