Hello,

         I am doing a test on exchange 2013 server by sending an email from telnet. My domain name is telka.com and I am trying to send an email to gmail.com and its sending without any authentication and my user called jdoe is receiving the mail. Please let us know how to stop this.

telnet mail.telka.com 25

220 esa.mail.telka.com ESMTP
helo
250 esa.mail.telka.com
mail from:susan@gmail.com
250 sender <susan@gmail.com> ok
rcpt to:jdoe@mail.telka.com
250 recipient <jdoe@mail.telka.com> ok
Data
354 go ahead
Subject:Test Email
Hi there this is just a test mail
.
250 ok:  Message 586337 accepted

quit
221 esa.mail.telka.com

hello

check you recive conector logs to wich connector mail raley and if got connector name check "remote network setting " for user ip

\Program Files\Microsoft\Exchange Server\V15\TransportRoles\Logs\FrontEnd\ProtocolLog\SmtpReceive

Hello

sorry.

but mail from is susan@gmail.com if you check smtp to open relay you need mail from susan@gmail.com and rcpt to: susan@gmail.com

telnet mail.telka.com 25

220 esa.mail.telka.com ESMTP
helo
250 esa.mail.telka.com
mail from:susan@gmail.com
250 sender <susan@gmail.com> ok
rcpt to:jdoe@mail.telka.com
250 recipient <jdoe@mail.telka.com> ok

Hi Syed,

According to your description, you want to send a email to gmail as a test, however, you send a test message to your domain user: jdoe;

If there is no mistake, as the sneff mentioned, you should check if your PC's IP in the"remote network setting" of relay connector.

Best regards,

no you got me wrong..

If you read carefully I am using GMAIL id mail from:susan@gmail.com  to send an email to my domain which is 

rcpt to:jdoe@mail.telka.com 

and I am receiving and email to my domain which is mail.telka.com

My question is why I am receiving since email from susan@gmail.com   since I am sending an email from my domain connecting from out side.

where I am telnetting my own server see the telnet session carefully.

telnet mail.telka.com 25

220 esa.mail.telka.com ESMTP
helo
250 esa.mail.telka.com
mail from:susan@gmail.com
250 sender <susan@gmail.com> ok
rcpt to:jdoe@mail.telka.com
250 recipient <jdoe@mail.telka.com> ok

Hello

go to ecp --> mail folw -->receive connector open deafult frontend connector and set ip-range

Hi Syed ,

Hope you are doing good.

Just tell me one thing from where you are trying to trigger that particular email .I mean is it from lan network or else from internet ?

Moreover above mentioned email is triggered from the sender "susan@gmail.com" to one of the recipient in your domain "jdoe@mail.telka.com" by using your mail server "mail.telka.com" .So obviously we will be having the sender as "susan@gmail.com" .

Please reply me if you have any queries.

Hello,

         I am doing a test on exchange 2013 server by sending an email from telnet. My domain name is telka.com and I am trying to send an email to gmail.com and its sending without any authentication and my user called jdoe is receiving the mail. Please let us know how to stop this.

telnet mail.telka.com 25

220 esa.mail.telka.com ESMTP
helo
250 esa.mail.telka.com
mail from:susan@gmail.com
250 sender <susan@gmail.com> ok
rcpt to:jdoe@mail.telka.com
250 recipient <jdoe@mail.telka.com> ok
Data
354 go ahead
Subject:Test Email
Hi there this is just a test mail
.
250 ok:  Message 586337 accepted

quit
221 esa.mail.telka.com

Hi Syed ,

One more thing i forget to say in my previous post.By default exchange 2013 servers will accept all the anonymous connections and it will not be on open relay. Anonymous connections are those which will come from internet or application servers or from other exchange organisations.

In your case sender is from gmail and the recipient is one of the user in your end so obviously your email server will accept the mails from external

Hello Nithya,

           Lets put this way now I am just using your name to mail my user with  in my organization ? but as a matter of fact you have not send me this email. 

telnet mail.telka.com 25

220 esa.mail.telka.com ESMTP
helo
250 esa.mail.telka.com
mail from:Nithya@gmail.com
250 sender <susan@gmail.com> ok
rcpt to:jdoe@mail.telka.com
250 recipient <jdoe@mail.telka.com> ok
Data
354 go ahead

Hello Nithya,

           Lets put this way now I am just using your name to mail my user with  in my organization ? but as a matter of fact you have not send me this email. 

     

telnet mail.telka.com 25

220 esa.mail.telka.com ESMTP
helo
250 esa.mail.telka.com
mail from:Nithya@gmail.com
250 sender <susan@gmail.com> ok
rcpt to:jdoe@mail.telka.com
250 recipient <jdoe@mail.telka.com> ok
Data
354 go

Thanks Andy that's exactly I wanted to know.  Can you please give me an example ? How exactly SPF record will help me out ? I have lot of documentation on SPF records over internet but it would be great if you could explain me in your own words ? and also how anti malware will detect that the mail is