On May 30, 2012, at 6:14 AM, Masoumeh Izadi wrote: > We have a postfix Email server . when someone telnet to port 25 on our > server, it is possible to send email from any ID user1@anydomain to any > user2@mydomain >
When an SMTP client connects to port 25 of your server, it is also possible to send email "from any ID user1@anydomain to any user2@mydomain". What is the problem you are trying to solve? If you have a problem with spam coming in this way, it is just as trivial to do so with some sort of SMTP client. > > The question is that: Is there any solution to prevent this matter or somehow > make postfix to authenticate the users telneting the server directly? No. To an SMTP server such as Postfix, there is no difference between an SMTP client and a Telnet client that is talking to it. SMTP clients essentially use the Telnet protocol to talk to an SMTP server. -- Larry Stone lston...@stonejongleux.com http://www.stonejongleux.com/
