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Thread: Using Telnet to send mail to local address

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  1. #1
    Join Date
    Apr 2006
    Barcelona (SPAIN)
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    Default Using Telnet to send mail to local address

    I know there is a flag on SMTP that leaves you send mail trough a server using Telnet login on port 25.
    On my zimbra server i cannot send to a foreign address (because relay in blocked), but i can send to an internal (existing) mail address (and if this is a distribution list...then i can send to foreign addresses...)

    For example:
    telnet 25
    Trying x.x.x.x
    Connected to
    Escape character is '^]'.
    220 ESMTP Postfix
    HELO abc
    250 2.1.0 Ok
    RCPT TO:
    250 2.1.5 Ok
    354 End data with .
    Subject: Test
    250 2.0.0 Ok: queued as A8999999999
    221 2.0.0 Bye
    Connection closed by foreign host.

    Doing this (from anywhere you want... local lan, outside...), the user receives an internal mail from

    As i said, I know tha this is the way smtp works (if the RCPT TO is inside the local server, the mail will be delivered). But, is there any way to lock/disable this for outside connections?

  2. #2
    Join Date
    Nov 2006
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