Telnet Based Server Testing

These tips and tricks detail the command syntax necessary to test common services using a telnet client. Network and System administrators can attest to how invaluable these types of tests can be when troubleshooting a system.

SMTP

% telnet mail.domain.com 25
Connected to mail.domain.com.
Escape character is '^]'.
220 mail.domain.com ESMTP
helo
250 mail.domain.com
mail from: User user@domain.com
250 ok
rcpt to User user@domain.com
250 ok
data
354 go ahead
From: User user@domain.com
To: User user@domain.com
Subject: Creative Thought Introduction
Hello. Allow me to introduce myself and my company, Creative Thought Inc. (CThought)
CThought provides network architecture, strategic planning and IT management based on our client's business models, goals and requirements. Services include onsite and remote IT management and system administration, system security and durability audits, business continuity/disaster recovery planning, and information technology policies, procedures and guidelines….
.
250 ok 1077217433 qp 12541
quit
221 mail.domain.com
Connection closed by foreign host./user@domain.com/user@domain.com/user@domain.com/user@domain.com

POP3

% telnet mail.domain.com 110
Connected to mail.domain.com.
Escape character is '^]'.
+OK
user user@domain.com
+OK
pass
+OK
stat
+OK 4 40856
list
+OK
1 35681
2 919
3 2617
4 1639
.
retr 4
+OK
From: User user@domain.com
To: User user@domain.com
Subject: Creative Thought Introduction
Hello. Allow me to introduce myself and my company, Creative Thought Inc. (CThought)
CThought provides network architecture, strategic planning and IT management based on our client's business models, goals and requirements. Services include onsite and remote IT management and system administration, system security and durability audits, business continuity/disaster recovery planning, and information technology policies, procedures and guidelines….
.
dele 4
+OK
quit
+OK
Connection closed by foreign host./user@domain.com/user@domain.com

imap4

telnet e-xbelize 143
Trying…
Connected to e-xbelize.austin.ibm.com.
Escape character is '^]'.
* OK IMAP4 server ready
. login id idpassword
. OK
. examine /usr/spool/mail/root
* FLAGS (Answered Flagged Draft Deleted Seen)
* OK [PERMANENTFLAGS (Answered Flagged Draft Deleted Seen *)]
* 0 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 823888143]
. OK [READ-ONLY] Examine completed
. logout
* BYE Server terminating connection
. OK Logout completed
Connection closed.

References
<a href="http://pages.prodigy.net/michael
santovec/pop3telnet.htm">Using Telnet with a POP3 Mail Server
Mail Server Testing
http://nscp.upenn.edu/aix4.3html/aixbman/commadmn/mlimappop.htm

HIPAA
HITRUST
FEDRAMP
ITAR
PCI
SOC