Connecting to smtp gmail com via command line

Question

I am in the process of writing an application that sends mail via an valid GMail user ID and password   I just wanted to simulate the SMTP connection on my Windows XP command line  and when I telnet smtp gmail com at 465 port - I don t see any thing  A blank command window with title Telnet smtp gmail com opens with cursor  When I type in EHLO or usual SMTP handshake commands  the prompt just closes    I am unable to figure out whats going wrong and where  I tried connecting to 587  it does not connect in telnet at all  Could anyone please clarify if I am doing something wrong

User · Answer

Try this   telnet smtp gmail com 587

User · Answer

For OSX  terminal   openssl s client -connect smtp gmail com 25 -starttls smtp

User · Answer

Jadaaih  you can connect send SMTP through CURL - link to Curl Developer Community    This is Curl Email Client source

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This is command for connect   server name  smtp gmail com server port  587 user name  hash  echo -n    user name      base64 user password  hash  echo -n    user password      base64   openssl s client -connect   server name     server port   -crlf -quiet -starttls smtp   and steps to accept message to send  auth login   user name  hash     user password  hash   helo   server name   mail from   lt   message from   gt  rcpt to   lt   message to   gt  DATA from   lt   message from   gt  to   lt   message to   gt  subject   message subject   Content-Type  text html  charset  UTF-8   Content-Transfer-Encoding  base64  MIME-Version  1 0   message content     quit

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Gmail require SMTP communication with their server to be encrypted   Although you re opening up a connection to Gmail s server on port 465  unfortunately you won t be able to communicate with it in plaintext as Gmail require you to use STARTTLS SSL encryption for the connection

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tcp 465 was initially intended for establishing the SSL and newer TLS  layer first  and inside doing cleartext or plain old protocols  smtp here   tcp 587 was intended as a replacement to default tcp 25 port initially when spammers and mass mailing attacks commenced like a decade or more ago  but also during those infamous AOL ages  when some funny ISP had some blocks on default ports outbound  such as that tcp 25  for denying their own customers  AOL  to mass-send emails spam back then  but AOL-customers needing to use alternative mail-accounts and mail-providers still needed to send their mails from AOL-internet connections  so they could still connect to tcp 587 and do simple smtp on it back then   The deal with the STARTTLS way to do smtp is to use the two well known originally plain-text tcp 25 and tcp 587 ports  and only when the initial clear-text connect suceeded  to then START the TLS layer  thus STARTTLS  from there on  having a secured connection from that point onwards   As for debugging these kind of things maybe via command-line tools  for example for windows there is the historical blat command line mailer  smtp   which up till today cant do TLS  STARTTLS  so it can only use plain-text smtp to send its mails   http   www blat net   Then there are numerous projects freeware and open source software that have more capabilities and features  such as  smtp client  mailsend   googlecode http   code google com p mailsend   smtp client  msmtp   sourceforge  related to mpop below  http   msmtp sourceforge net   pop3 client  mpop   sourceforge http   mpop sourceforge net

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Check this post in lifehacker   Geek to Live  Back up Gmail with fetchmail   It uses a command line program  Check and see if it helps  BTW why are you using command line when there are many other nice alternatives

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Using Linux or OSx  do what Sorin recommended but use port 465 instead  25 is the generic SMTP port  but not what GMail uses  Also  I don t believe you want to use -starttls smtp  openssl s client -connect smtp gmail com 465   You should get lots of information on the SSL session and the response    220 mx google com       Type in   HELO smtp gmail com    and you ll receive    250 mx google com at your service   From there it is not quite as straightforward as just sending SMTP messages because Gmail has protections in place to ensure you only send emails appearing to be from accounts that actually belong to you  Instead of typing in  Helo   use  Ehlo   I don t know much about SMTP so I cannot explain the difference  and don t have time to research much  Perhaps someone with more knowledge can explain     Then  type  auth login  and you will receive the following    334 VXNlcm5hbWU6   This is essentially the word  Username  encoded in Base 64  Using a Base 64 encoder such as this one  encode your user name and enter it  Do the same for your password  which is requested next  You should see    235 2 7 0 Accepted   And that s it  you re logged in   There is one more oddity to overcome if you re using OSx or Linux terminals  Just pressing the  ENTER  key does not apparently result in a CRLF which SMTP needs to end a message  You have to use  CTRL V ENTER   So  this should look like the following     M   M 250 2 0 0 OK

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Start session from terminal   openssl s client -connect smtp gmail com 25 -starttls smtp  The last line of the response should be  250 SMTPUTF8   Initiate login  auth login  This should return  334 VXNlcm5hbWU6    Type username  Type your username in base64 encoding  eg  echo -n  your-username    base64   This should return  334 UGFzc3dvcmQ6   Type password  Type your password in base64 encoding  eg  echo -n  your-password    base64   Success  You should see  235 2 7 0 Accepted  and you re are successfully logged in

User · Answer

gmail uses an encrypted connection  So  even after you establish a connection  you wont be able to send any email  The encryption is a little complex to manage  Try using openssl instead   The thread below should help-  How to send email using simple SMTP commands via Gmail

[smtp] Connecting to smtp.gmail.com via command line

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