Re: Telnet port 25

From: Miller, Dave (I.S.) (Dave.Miller_at_BHS.ORG)
Date: 12/15/03

  • Next message: Harvey, Bruce T.: "FastWrite and its effect on SSARaid Adapters and Performance" 
    Date:         Mon, 15 Dec 2003 06:59:03 -0500
To: aix-l@Princeton.EDU

    Thanks!

    -----Original Message-----
    From: Adams Kevin J [mailto:kevin.adams@PHS.COM]
    Sent: Friday, December 12, 2003 8:16 PM
    To: aix-l@Princeton.EDU
    Subject: Re: Telnet port 25

    Found this on Google:

    "The tcpd wrapper can even be used to control access to the smtp port.
    This can be useful when you suspect that someone is trying out some
    obscure sendmail bug, or when a remote site is misconfigured and keeps
    hammering your mail daemon.

    In that case, sendmail should not be run as a stand-alone daemon, but
    it should be registered in the inetd configuration file. For example:

        smtp stream tcp nowait root /usr/etc/tcpd
    /usr/lib/sendmail
    -bs

    You will periodically want to run sendmail to process queued-up
    messages. A crontab entry like:

        0,15,30,45 * * * * /usr/lib/sendmail -q

    should take care of that. You cannot really prevent people from posting
    forged mail this way, because there are many unprotected smtp daemons
    on the network."

    Kevin Adams
    PacifiCare Behavioral Health
    Principal Systems Analyst
    AIX CATE

    -----Original Message-----
    From: Bob Booth - UIUC [mailto:booth@UIUC.EDU]
    Sent: Wednesday, December 10, 2003 10:50 AM
    To: aix-l@Princeton.EDU
    Subject: Re: [aix-l] Telnet port 25

    You took the words right out of my email... ;-) I think this is very
    possible, however, depending on the number of people you want to 'talk'
    to
    you, it could be a very long hosts.allow list... But quite do-able.

    bob

    On Wed, Dec 10, 2003 at 10:47:21AM -0800, Robert Miller wrote:
    > Not sure if it's possible with vanilla sendmail, it may be... but I
    > wonder if you could do such a thing with TCPWrappers? If you could
    > start sendmail using TCPWrappers, that would allow you to use the
    > hosts.allow and hosts.deny files to say which boxes could talk to your
    > smtp port...
    >
    > Not sure if it's possible... anyone know if this even sounds feasible?
    >
    > --rm
    >
    > -----Original Message-----
    > From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU]On Behalf Of
    > Miller, Dave (I.S.)
    > Sent: Wednesday, December 10, 2003 10:31 AM
    > To: aix-l@Princeton.EDU
    > Subject: Re: Telnet port 25
    >
    >
    > Thanks for the replies.
    > Maybe I should ask/approach this way...can I limit telnet to respond
    > only to certain IP addresses, or sendmail relays for that matter?
    > thanks
    >
    > -----Original Message-----
    > From: Bill Verzal [mailto:BVerzal@KOMATSUNA.COM]
    > Sent: Wednesday, December 10, 2003 12:22 PM
    > To: aix-l@Princeton.EDU
    > Subject: Re: Telnet port 25
    >
    >
    > smtp runs on port 25. You do not need sendmail running to send mail
    out
    > of
    > a box. Once you stop sendmail, telnet to port 25 will be closed.
    >
    > BV
    > --------------------------------------------------------
    >
    > "If everything is coming your way, then you are in the wrong lane"
    >
    > Bill Verzal
    > AIX Administrator, Komatsu America
    > (847) 970-3726 - direct
    > (847) 970-4184 - fax
    >
    >
    >
    > "Miller, Dave
    > (I.S.)"
    > <Dave.Miller@BHS.
    > To
    > ORG> aix-l@Princeton.EDU
    > Sent by: IBM AIX
    > cc
    > Discussion List
    > <aix-l@Princeton.
    > Subject
    > EDU> Telnet port 25
    >
    >
    > 12/10/2003 11:10
    > AM
    >
    >
    > Please respond to
    > IBM AIX
    > Discussion List
    > <aix-l@Princeton.
    > EDU>
    >
    >
    >
    >
    >
    >
    > Can someone point me in the write direction as to how I would easily
    > disallow telnet to port 25, but still allow telnet to port 23?
    >
    >
    > I.e. I don't want to be able to telnet to port 25 and send mail, but I
    > still want to run sendmail, and allow telnet... or am I looking at
    this
    > wrong? Thanks.
    >
    >
    >
    >
    >
    >
    >
    >
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    > CONFIDENTIALITY NOTICE: This email communication and any attachments
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    > contain confidential and privileged information for the use of the
    > designated recipients named above. If you are not the intended
    > recipient, you are hereby notified that you have received this
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    > received this communication in error, please reply to the sender
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    This electronic message transmission, including any attachments,
    contains
    information from PacifiCare Health Systems Inc. which may be
    confidential or
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  • Next message: Harvey, Bruce T.: "FastWrite and its effect on SSARaid Adapters and Performance"

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    • Re: Telnet port 25
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