IMAP via Telnet

To ensure that Dovecot is authenticating and responding properly, we can use telnet to verify if it is working:

$ telnet localhost 143
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE NAMESPACE LITERAL+ STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready.

Now you type the login command with a strange number preceeding:

1 Login Email Password
1 OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW STATUS=SIZE SAVEDATE NAMESPACE LITERAL+ NOTIFY SPECIAL-USE COMPRESS=DEFLATE QUOTA] Logged in

Now you select the inbox.

1 SELECT Inbox
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags permitted.
* 6273 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1567592696] UIDs valid
* OK [UIDNEXT 31618] Predicted next UID
* OK [HIGHESTMODSEQ 53315] Highest
1 OK [READ-WRITE] Select completed (0.017 + 0.000 + 0.016 secs).

You see that 6273 mails exist.

Now you type the logout command:

1 LOGOUT
* BYE Logging out
1 OK Logout completed (0.001 + 0.000 secs).
Connection closed by foreign host.