В данной статье будем рассматривать как проверить состоияние сервисов на хосте

Состояние POP3

#telnet pop3.telnet.test pop3
telnet: Connected to pop3.telnet.test.
telnet: Escape character is '^]'.
server: +OK Dovecot ready.
client: USER MyUsername
server: +OK
client: PASS MyPassword
server: +OK Logged in.
client: LIST
server: +OK 3 messages:
server: 1 114005
server: 2 6663
server: 3 1392651
server: .
client: RETR 1
server: +OK 2287 octets
server:Return-Path: <test3@pop3.telnet.test
server:X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pop3.telnet.test
server:X-Spam-Level: *
server:.
client: DELE 1
 server: +OK Marked to be deleted.
 client: quit
 server: +OK Logging out, messages deleted.
 server: Connection closed by foreign host.

Состояние IMAP

# telnet imap.telnet.test imap

 telnet: Connected to imap.telnet.test.
telnet: Escape character is '^]'.
server: Connected to localhost.
Escape character is '^]'.
server:* OK Dovecot ready..
client: a1 LOGIN MyUsername MyPassword
server: a1 OK Logged in
client: a2 LIST "" "*"
server: * LIST (\HasNoChildren) "." "Junk"
server: * LIST (\HasNoChildren) "." "Trash"
server:* LIST (\HasNoChildren) "." "Sent"
server:* LIST (\HasNoChildren) "." "Drafts"
server:* LIST (\HasNoChildren) "." "INBOX"
server:a2 OK List completed.
client: a3 SELECT INBOX
server:* OK [CLOSED] Previous mailbox closed.
server:* FLAGS (\Answered \Flagged \Deleted \Seen \Draft $MDNSent)
server:* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft $MDNSent \*)] Flags permitted.
server:* 18 EXISTS
server:* 0 RECENT
server:* OK [UIDVALIDITY 1358519219] UIDs valid
server:* OK [UIDNEXT 423] Predicted next UID
server:* OK [HIGHESTMODSEQ 960] Highest
server:a4 OK [READ-WRITE] Select completed.
client: a5 FETCH 1 BODY[]
server: * 1 FETCH (BODY[] {405}
server: Return-Path: sender@imap.telnet.test
server: Received: from imap.telnet.test
server: by mx1.imap.telnet.test with ESMTP
server: From: sender@imap.telnet.test
server: Subject: Test message
server: To: recipient@imap.telnet.test
server: Message-Id: <20040120203404.CCCC18555.mx1.imap.telnet.test@ient.imap.telnet.test>
server:
server: This is a test message.
server: )
server: a5 OK Fetch completed.
client: a6 LOGOUT
server: * BYE Logging out
server: a6 OK Logout completed.

Состояние SMTP

# telnet smtp.telnet.test 25
Connected to smtp.telnet.test.
Escape character is '^]'.
server:220 smtp.telnet.test ESMTP Postfix
client:HELO smtp.telnet.test
server:250 smtp.telnet.test
client:MAIL FROM: roman@smtp.telnet.test
server:250 2.1.0 Ok
client:RCPT TO: drake@smtp.telnet.test
server:250 2.1.5 Ok
client:DATA
server:server:354 End data with .
client:Subject: Test
client:
client:hello
client:.
server:250 2.0.0 Ok: queued as B822840153
client:QUIT
server:221 closing connection