How to fix it in mail server?

Help! (Home for newbies)
1 
My Domain : skynetisp.ca ;
MY system : centos 6.4
                 virtualmin 4.06.gpl GPL
                 Webmin version 	1.650
                 Postfix 2.6.6

Using the test tool: https://www.wormly.com/test_smtp_server i was able to do this:

1) Fake user Greg to send email to true user Tom
ex: greg@skynetisp.ca   to   tom@skynetisp.ca ------------------------HOW TO FIX IT I DONT WANT THIS TO HAPPEN ?

Resolving hostname...
Connecting...
SMTP -> FROM SERVER:
220 skynetisp.ca ESMTP Postfix
SMTP -> FROM SERVER:
250-skynetisp.ca
250-PIPELINING
250-SIZE 104857600
250-ETRN
250-STARTTLS
250-AUTH LOGIN PLAIN
250-AUTH=LOGIN PLAIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
MAIL FROM: greg@skynetisp.ca
SMTP -> FROM SERVER:
250 2.1.0 Ok
RCPT TO: tom@skynetisp.ca
SMTP -> FROM SERVER:
250 2.1.5 Ok
Sending Mail Message Body...
SMTP -> FROM SERVER:
354 End data with .
SMTP -> FROM SERVER:
250 2.0.0 Ok: queued as C34372843
Message completed successfully.

2) True user to true user:
ex: tom@skynetisp.ca  to  bob@skynetisp.ca ------------------------ HOW TO FIX IT I DONT WANT THIS TO HAPPEN ?


Resolving hostname...
Connecting...
SMTP -> FROM SERVER:
220 skynetisp.ca ESMTP Postfix
SMTP -> FROM SERVER:
250-skynetisp.ca
250-PIPELINING
250-SIZE 104887600
250-ETRN
250-STARTTLS
250-AUTH LOGIN PLAIN
250-AUTH=LOGIN PLAIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
MAIL FROM: bob@skynetisp.ca
SMTP -> FROM SERVER:
250 2.1.0 Ok
RCPT TO: tom@skynetisp.ca
SMTP -> FROM SERVER:
250 2.1.5 Ok
Sending Mail Message Body...
SMTP -> FROM SERVER:
354 End data with .
SMTP -> FROM SERVER:
250 2.0.0 Ok: queued as C35379844
Message completed successfully.

Thanks All !

2

Howdy,

I don’t have any experience running Virtualmin on a Synology system. That’s also using a pretty old version of Virtualmin there, if it’s possible to upgrade I’d recommend it.

But can you describe what it is that you want to have happen, instead of what’s happening above?

-Eric

3

Thank you for reply !

I want to not be able to fake accounts in my system to avoid spamming impersonation. Because https://www.wormly.com/test_smtp_server can use one account impersonating someone in the system to send as what I mentioned.

I need my system works :

  • internal ----> internal == ok send ( ex : tom@skynetisp.ca —> peter@skynetisp.ca = ok send )

  • external -----> internal ==ok send (ex : tom@gmail.com ----> tom@skynetisp.ca = ok send )

  • internal -------> external ==ok send ( ex : tom@skynetisp.ca----> tom@yahoo.com = ok send )

  • https://www.wormly.com/test_smtp_server ------> internal == Not send ( ex: tom@skynetisp.ca —) peter@skynetisp.ca == not send )

( Note : Present https://www.wormly.com/test_smtp_server can forge any account in my system to send to the internal mail )

@andreychek

4

Can you help me ?

5

Can you help me ?

@andreychek