Tag: smtp
Using telnet to access pop3 (retrieve emails) and smtp (send emails)
by z3n on Jan.11, 2010, under Uncategorized
Problem:
How to test retrieve and send emails by raw telnet?
Solution:
Retrieving emails (bold lines are the commands, italics are outputs)
telnet mail.yourserver.com 110
Trying 1.2.3.4…
Connected to mail.yourserver.com.
Escape character is ‘^]’.
+OK Dovecot ready.
user your_email@yourserver.com
+OK
pass your_password
+OK Logged in.
list
+OK 1 messages:
1 1133
.
retr 1
message
.
quit
Sending emails:
telnet mail.youremailserver.com 25
Trying 1.2.3.4…
Connected to mail.youremailserver.com.
Escape character is ‘^]’.
220 youremailserver.com ESMTP Postfix
helo yourdomain.com
250 youremailserver.com
auth login
334 VXNlcm5hbWU6
eW91cmVtYWlsQHlvdXJkb21haW4uY29t (youremail@yourdomain.com base64 encoded)
334 UGFzc3dvcmQ6
eW91cnBhc3N3b3Jk (yourpassword base64 encoded)
235 2.0.0 Authentication successful
mail from:youremail@yourdomain.com
250 2.1.0 Ok
rcpt to: someone@somedomain.com
250 2.1.5 Ok
data
354 End data with <CR><LF>.<CR><LF>
subject: test
hi
.
250 2.0.0 Ok: queued as 8B65ED40075
quit
Note that there’s many different authentication protocols, base64 is the less secure one, some servers may require a better authentication mechanism, or even use an ecrypted port, which will not work with telnet, try open ssl instead.
Sendmail: Relaying Denied: Proper Authentication Required
by z3n on Dec.08, 2009, under Linux Happyness, Tips & Hints
Problem:
You can receive emails with your own mail server, but can’t send to “non-local” domains.
Solution:
You need to setup auth method before sending emails outside the local realm. You can enable ecrypted passwords and such.
Change at sendmail config:
define(`confAUTH_OPTIONS’, `A’)dnl
TRUST_AUTH_MECH(`LOGIN PLAIN’)dnl
define(`confAUTH_MECHANISMS’, `LOGIN PLAIN’)dnl
at ssh:
set auth_options to `A’
service saslauthd restart (don’t forget it’s importaint)
service sendmail restart
