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Thread: Configuration issue with Sendmail TLS on Ubuntu

  1. #1
    Join Date
    May 2013
    Beans
    7

    Configuration issue with Sendmail TLS on Ubuntu

    Hi,

    We have sendmail running on a virtual Ubuntu server which is acting as a relay server. We are trying to configure TLS encryption on sendmail.
    We have configured using the following link: http://weldon.whipple.org/sendmail/starttlstut.html

    After configuration, we can see the below status in telnet:

    Trying 127.0.0.1...
    Connected to
    Escape character is '^]'.
    220 ESMTP Sendmail 8.14.4/8.14.4/Debian-2ubuntu1; Fri, 21 Jun 2013 10:35:21 +0100; (No UCE/UBE) logging access from: (OK)-[127.0.0.1]
    ehlo localhost
    250-Hello [127.0.0.1], pleased to meet you
    250-ENHANCEDSTATUSCODES
    250-PIPELINING
    250-EXPN
    250-VERB
    250-8BITMIME
    250-SIZE
    250-DSN
    250-ETRN
    250-AUTH DIGEST-MD5 CRAM-MD5
    250-STARTTLS
    250-DELIVERBY
    250 HELP

    The emails are being delivered successfully. However, after sending emails the email logs do not show any entry for TLS.Also the message headers of the email do not contain information about TLS.

    Ubuntu details:
    DISTRIB_ID=Ubuntu
    DISTRIB_RELEASE=11.04
    DISTRIB_CODENAME=natty
    DISTRIB_DESCRIPTION="Ubuntu 11.04"

    Sendmail version: 8.14.4

    Kindly suggest if we are missing something.
    Last edited by Riunixteam; June 21st, 2013 at 10:44 AM.

  2. #2
    Join Date
    May 2013
    Beans
    7

    Re: Configuration issue with Sendmail TLS on Ubuntu

    Hi,

    Please check and suggest regarding this.

  3. #3
    Join Date
    Mar 2006
    Location
    The Internet
    Beans
    1,817
    Distro
    Ubuntu

    Re: Configuration issue with Sendmail TLS on Ubuntu

    Are you referring to SMTP-TLS?

    I would suggest using postfix instead of sendmail. Postfix is far easier to configure.

    Cheers,

  4. #4
    Join Date
    May 2013
    Beans
    7

    Re: Configuration issue with Sendmail TLS on Ubuntu

    Ues SMTP-TLS. We cannot change the server setup. We have to use sendmail with TLS. Please suggest why the headers do not show TLS encryption. Does that mean that the server is not using TLS correctly?

  5. #5
    Join Date
    Nov 2008
    Location
    Boston MetroWest
    Beans
    16,326

    Re: Configuration issue with Sendmail TLS on Ubuntu

    If you can deploy another virtual server, I recommend you install a copy of CentOS 6.4 and install sendmail on that. I don't usually have to do anything to get it to use TLS, though by default it uses a "snakeoil" cert in /etc/pki/tls. You can replace that with your own certificate if you purhased one.

    On the CentOS platform, I routinely install the MailScanner package that includes MailScanner itself, SpamAssassin, and ClamAV. The default configuration scans every message for viruses with ClamAV and for spam with SpamAssassin. The first are quarantined, while spam is quarantined or tagged and delivered depending on a message's SpamAssassin score.

    My server shows log entries like these when it sends a message to a remote site that uses TLS:
    Code:
    Jul  2 19:04:20 xxxxx sendmail[31387]: STARTTLS=client, relay=gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL, cipher=RC4-SHA, bits=128/128
    The failed verification comes from using a certificate not signed by a trusted root.

    However I don't see any inbound mail that uses TLS. All our inbound mail arrives via ESMTP. Here, for instance, is an inbound message from GMail:
    Code:
    Jul  2 08:10:11 xxxxx sendmail[30723]: r62CAB0K030723: from=<someone@gmail.com>, size=1783, class=0, nrcpts=1, msgid=CAEpVZbSPRgPEAURHyT=5QYhzin7A6_tuGfLxKq+Xc9VqcsSCFA@mail.gmail.com>, proto=ESMTP, daemon=MTA, relay=mail-vb0-f49.google.com [209.85.212.49]
    Are you looking to configure sendmail to force remote sending servers to prefer TLS? If so, this looks like a good starting point.
    Last edited by SeijiSensei; July 3rd, 2013 at 01:05 AM.
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