Re: Setting up email on Slack 11.0 - Slackware

This is a discussion on Re: Setting up email on Slack 11.0 - Slackware ; On Thu, 04 Oct 2007 19:06:48 +0000, Rich Grise wrote: > On Thu, 04 Oct 2007 18:46:06 +0000, Rich Grise wrote: > >> I've asked about setting up the company's "server", actually just a >> gateway for the lan, with ...

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Thread: Re: Setting up email on Slack 11.0

  1. Re: Setting up email on Slack 11.0

    On Thu, 04 Oct 2007 19:06:48 +0000, Rich Grise wrote:

    > On Thu, 04 Oct 2007 18:46:06 +0000, Rich Grise wrote:
    >
    >> I've asked about setting up the company's "server", actually just a
    >> gateway for the lan, with Samba, Apache, proftpd, and whatever comes
    >> out of the box. I'm on a dynamic IP, but www.zoneedit has given me
    >> a nice script to update the nameserver when I get a new IP, like
    >> when we have to reboot "the server".


    OK, just to show I'm not only sitting on my butt here, I see
    /etc/mail/sendmail.cf, but it says:
    ################################################## ###################
    ################################################## ####################
    #####
    ##### SENDMAIL CONFIGURATION FILE
    #####
    ##### built by root@tree on Sat Sep 30 19:34:03 CDT 2006
    ##### in /tmp/sendmail-8.13.8/cf/cf
    ##### using ../ as configuration include directory
    #####
    ################################################## ####################
    #####
    ##### DO NOT EDIT THIS FILE! Only edit the source .mc file.
    #####
    ################################################## ####################
    ################################################## ####################
    ------------

    But
    user@ABIServer:/etc/mail
    $ find / -name sendmail.mc -print 2> /dev/null
    user@ABIServer:/etc/mail
    $

    So, ???????

    Thanks,
    Rich



  2. Re: Setting up email on Slack 11.0

    On Thu, 04 Oct 2007 19:13:47 +0000, Rich Grise wrote:

    > user@ABIServer:/etc/mail
    > $ find / -name sendmail.mc -print 2> /dev/null
    > user@ABIServer:/etc/mail
    > $
    >
    > So, ???????


    OK, so I try it as root:
    ----------
    root@ABIServer:~
    # find / -name sendmail.mc -print
    find: WARNING: Hard link count is wrong for /proc: this may be a bug in
    your filesystem driver. Automatically turning on find's -noleaf option.
    Earlier results may have failed to include directories that should have
    been searched.
    root@ABIServer:~
    #
    ------------
    Now I'm frightened.

    Thanks,
    Rich


  3. Re: Setting up email on Slack 11.0

    On Thu, 04 Oct 2007 19:20:28 +0000, Rich Grise wrote:
    > On Thu, 04 Oct 2007 19:13:47 +0000, Rich Grise wrote:
    >> user@ABIServer:/etc/mail
    >> $ find / -name sendmail.mc -print 2> /dev/null
    >> user@ABIServer:/etc/mail
    >> $
    >>
    >> So, ???????

    >
    > OK, so I try it as root:
    > ----------
    > root@ABIServer:~
    > # find / -name sendmail.mc -print
    > find: WARNING: Hard link count is wrong for /proc: this may be a bug in
    > your filesystem driver. Automatically turning on find's -noleaf option.
    > Earlier results may have failed to include directories that should have
    > been searched.
    > root@ABIServer:~
    > #
    > ------------
    > Now I'm frightened.


    OK, I lied:
    ------
    root@ABIServer:~
    # find / -name "sendmail*" -print
    /etc/mail/sendmail.cf
    /pub/Server/Rich/sendmail.8.13.7.tar
    /var/log/packages/sendmail-cf-8.13.8-noarch-4
    /var/log/packages/sendmail-8.13.8-i486-4
    /var/log/scripts/sendmail-8.13.8-i486-4
    /usr/bin/sendmail
    /usr/doc/sendmail-8.13.8
    /usr/lib/php/Mail/sendmail.php
    /usr/lib/sendmail
    /usr/man/man8/sendmail.8.gz
    /usr/sbin/sendmail
    /usr/local/home/user/ServerCopy/Rich/sendmail.8.13.7.tar
    /usr/share/jed/lib/sendmail.sl
    /usr/share/emacs/21.4/lisp/mail/sendmail.el
    /usr/share/emacs/21.4/lisp/mail/sendmail.elc
    /usr/share/sendmail
    /usr/share/sendmail/cf/cf/sendmail-slackware-tls.mc
    /usr/share/sendmail/cf/cf/sendmail-slackware-tls-sasl.mc
    /usr/share/sendmail/cf/cf/sendmail-slackware.mc
    /usr/share/sendmail/sendmail-slackware-tls.cf
    /usr/share/sendmail/sendmail-slackware-tls-sasl.cf
    /usr/share/sendmail/sendmail-slackware.cf
    find: WARNING: Hard link count is wrong for /proc: this may be a bug in your filesystem driver. Automatically turning on find's -noleaf option. Earlier results may have failed to include directories that should have been searched.
    root@ABIServer:~
    #
    -----

    But I'm still at a loss; but I think I'll at least LOOK at
    /usr/share/sendmail/cf/cf/sendmail-slackware.mc ,
    but I still have to do all of that other stuff that I have no idea how
    to do or what.

    Kinda like those dreams where I know there's something vitally important
    that I absolutely must do, but have no clue what it is. Or, I'm in
    school, and can't find my locker and have no idea what room I'm supposed
    to go to.

    Thanks,
    Rich


  4. Re: Setting up email on Slack 11.0

    On Thu, 04 Oct 2007 20:43:21 +0000, Rich Grise wrote:
    >
    > But I'm still at a loss; but I think I'll at least LOOK at
    > /usr/share/sendmail/cf/cf/sendmail-slackware.mc ,
    > but I still have to do all of that other stuff that I have no idea how
    > to do or what.
    >


    OK, I've got /usr/share/sendmail/cf/cf/sendmail-slackware.mc up on
    a console, and I still have no clue.

    Thanks,
    Rich


  5. Re: Setting up email on Slack 11.0

    Rich Grise wrote:
    > On Thu, 04 Oct 2007 19:06:48 +0000, Rich Grise wrote:


    >
    > But
    > user@ABIServer:/etc/mail
    > $ find / -name sendmail.mc -print 2> /dev/null
    > user@ABIServer:/etc/mail
    > $
    >
    > So, ???????
    >


    Install the sendmail-cf package and look in the
    /usr/share/sendmail/cf/cf directory.
    Your sendmail.cf was probably generated from
    sendmail-slackware.mc. The /etc/mail/sendmail.cf files
    in recent slackware releases have the text of the
    ..mc file appended as comment at the end of the .cf file.

    Start with reading /usr/share/sendmail/cf/README

    Regards,

    Kees.

    --
    Kees Theunissen.

  6. Re: Setting up email on Slack 11.0

    Rich Grise wrote:
    > On Thu, 04 Oct 2007 20:43:21 +0000, Rich Grise wrote:
    >> But I'm still at a loss; but I think I'll at least LOOK at
    >> /usr/share/sendmail/cf/cf/sendmail-slackware.mc ,
    >> but I still have to do all of that other stuff that I have no idea how
    >> to do or what.
    >>

    >
    > OK, I've got /usr/share/sendmail/cf/cf/sendmail-slackware.mc up on
    > a console, and I still have no clue.


    I'll come back on this later.
    First let's examen if you would/should run your own server on a
    dynamic Ip number. I mentioned some problems in my first posting
    on this thread. After that you mentioned your domain name in
    an other posting. So let's have a closer view on the details.
    First do a nameserver lookup of the domain:

    kees@lankhmar:~$ nslookup
    > set type=any
    > abiengr.com

    Server: 127.0.0.1
    Address: 127.0.0.1#53

    Non-authoritative answer:
    Name: abiengr.com
    Address: 71.103.120.74
    abiengr.com
    origin = ns8.zoneedit.com
    mail addr = soacontact.zoneedit.com
    serial = 1104174741
    refresh = 14400
    retry = 7200
    expire = 950400
    minimum = 7200
    abiengr.com nameserver = ns17.zoneedit.com.
    abiengr.com nameserver = ns8.zoneedit.com.

    Authoritative answers can be found from:
    abiengr.com nameserver = ns8.zoneedit.com.
    abiengr.com nameserver = ns17.zoneedit.com.

    I'll elaborate on two lines of the above 'nslookup'
    output: "Address: 71.103.120.74" and "minimum = 7200".
    Let's start with the latter: "minimum = 7200".
    The meaning of this parameter is not clear and has
    changed over time. Interpretation of this parameter
    by clients is implementation dependent. A client might
    use this a the allowed time to cache lookups.
    Your current value is 7200 seconds (2 hours). If some
    server sends a message to you, it could cache your
    IP number for two hours and just try to deliver a
    second message, within this 2 hour period, to the same
    address. And if your IP number happened to change between
    the first and the second message you're in trouble.
    This means that there is a window of maximal two hours
    that a remote email server could try to deliver a
    message to your old IP number. If you're lucky the
    new user of your old IP number has no mail server running.
    In that case delivery attempts will fail, the message will
    be queued for some time and delivery will be retried
    later. But if you're unlucky the new user of your old IP
    number will be running a mail server too. In that case
    he/she will likely reject messages addressed to you
    with a _permanent_ failure. (What happens whenever
    this new owner or your old IP number _accepts_ _your_
    messages is left to your imagination.)
    It should be clear that mail delivery is not reliable
    during this 2 hour time frame. Can this frame size be
    reduced? Yes. I'm not a zoneedit.com user but some
    googleing showed a minimum value of 1200 (20 minutes).
    This still means that there will always be a problem
    window of at least 20 minutes. Mail delivery will be
    unreliable during this window. This is all about,
    for now, the "minimum = 7200" in the "nslookup"
    output. Till now we ware talking about inbound
    messages.

    Now let's have a look at the transmission of
    outbound messages. This is where the other line
    "Address: 71.103.120.74" of nslookup's output
    comes in action. You're connecting to a remote
    mail server and your IP number is 71.103.120.74.
    The remote server will perform a reverse lookup of
    that IP number and will get the name:
    "pool-71-103-120-74.lsanca.dsl-w.verizon.net".
    The string "dsl" is part of your host name, as well
    as a complete representation of your IP number:
    "71-103-120-74". This is a fail-sure indication
    of an end user address space; and that happens to
    be the space where almost all spam bots are
    hanging out. Lots of mail servers will refuse
    your mail, only based on your IP number and
    without even examining your message.

    Do you still want/need to run your own mail server?
    In that case let's look at your question:
    "I've got /usr/share/sendmail/cf/cf/sendmail-slackware.mc
    up on a console, and I still have no clue".
    What should be adjusted?
    The default sendmail configuration is quite appropriate
    for systems running with a static public IP number and
    whose reverse dns lookup does point to their host
    name. But if you are hidden on a private network behind
    at "natting" adsl modem, you'll need to adjust quite a
    lot.

    The output of the command:
    echo "$=w" | sendmail -bt -d0
    will show your sendmail's knowledge of its environment.
    Here is my workstation at home, hidden on at natted network:

    ~$echo "$=w" | sendmail -bt -d0
    Version 8.13.8
    Compiled with: DNSMAP LOG MAP_REGEX MATCHGECOS MILTER
    MIME7TO8 MIME8TO7 NAMED_BIND NETINET NETUNIX
    NEWDB NIS PIPELINING SASLv2 SCANF
    SOCKETMAP STARTTLS TCPWRAPPERS USERDB XDEBUG

    ============ SYSTEM IDENTITY (after readcf) ============
    (short domain name) $w = lankhmar
    (canonical domain name) $j = lankhmar.remmin.home
    (subdomain name) $m = remmin.home
    (node name) $k = lankhmar
    ================================================== ======

    ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
    Enter

    > localhost

    [192.168.1.3]
    [127.0.0.1]
    lankhmar.remmin.home
    lankhmar


    The first part of this output is debugging output caused by
    the option -d0 to sendmail. This shows, among else, sendmails
    idea of its host name ($w), domain ($m) and fully qualified
    domain name ($j). And it should be clear that none of these
    values should ever show up during communication with external
    mail servers. Some tuning would be needed if I wanted to use
    this system as a public mail server!
    The last few lines of the above cited output ("> localhost"
    and later) are the result oft the "$=w" input to sendmail.
    These show the names and IP numbers (the IP numbers between
    square brackets) that are recognized as "local". Without
    further configuration sendmail will only accept messages
    that have one of these names or [numbers] a the destination.

    So the output of the above mentioned command:
    echo "$=w" | sendmail -bt -d0
    will give you a clue _what_ needs to be configured. _How_
    this can be done will probably be your next question.

    In addition to all this you might want to run a virus
    scanner and a spam filter. Did I mention already running
    an IMAP or a POP server, so that your user(s) can retrieve
    the mail to their workstations?


    Regards,

    Kees.

    --
    Kees Theunissen.

  7. Re: Setting up email on Slack 11.0

    On Fri, 05 Oct 2007 07:21:17 +0200, Kees Theunissen wrote:
    > Rich Grise wrote:
    >> On Thu, 04 Oct 2007 20:43:21 +0000, Rich Grise wrote:
    >>> But I'm still at a loss; but I think I'll at least LOOK at
    >>> /usr/share/sendmail/cf/cf/sendmail-slackware.mc ,
    >>> but I still have to do all of that other stuff that I have no idea how
    >>> to do or what.
    >>>

    >>
    >> OK, I've got /usr/share/sendmail/cf/cf/sendmail-slackware.mc up on
    >> a console, and I still have no clue.

    >
    > I'll come back on this later.
    > First let's examen if you would/should run your own server on a
    > dynamic Ip number.


    [excellent sendmail treatise snipped]

    Thank you very much for this. It looks like my options are:
    1. Copy your whole posting and show it to the PHB, and say, "It's
    strongly recommended NOT to run a mail server on a dynamic IP, so
    the best option is to continue to redirect email to your AOL account",
    or
    2. Tell the PHB to call Verizon and find out how much it would cost
    to get a static IP, at which point configuring email would be worthwhile?

    Do you have a recommendation here?

    And yes, I knew I'd have to do something about POP3, and get the Windows
    local users some kind of mail client, but that's just another of my
    questions.

    Thanks,
    Rich


  8. Re: Setting up email on Slack 11.0

    On Fri, 05 Oct 2007 07:21:17 +0200, Kees Theunissen wrote:

    > Rich Grise wrote:
    >> On Thu, 04 Oct 2007 20:43:21 +0000, Rich Grise wrote:
    >>> But I'm still at a loss; but I think I'll at least LOOK at
    >>> /usr/share/sendmail/cf/cf/sendmail-slackware.mc ,
    >>> but I still have to do all of that other stuff that I have no idea how
    >>> to do or what.
    >>>

    ....
    > The output of the command:
    > echo "$=w" | sendmail -bt -d0
    > will show your sendmail's knowledge of its environment.
    > Here is my workstation at home, hidden on at natted network:


    [snip]

    OK, here's my output to the same command:
    --------------------

    user@ABIServer:~
    $ echo "$=w" | sendmail -bt -d0
    Version 8.13.8
    Compiled with: DNSMAP LOG MAP_REGEX MATCHGECOS MILTER MIME7TO8 MIME8TO7
    NAMED_BIND NETINET NETUNIX NEWDB NIS PIPELINING SASLv2 SCANF
    SOCKETMAP STARTTLS TCPWRAPPERS USERDB XDEBUG

    ============ SYSTEM IDENTITY (after readcf) ============
    (short domain name) $w = ABIServer
    (canonical domain name) $j = ABIServer.dsl-verizon.net
    (subdomain name) $m = dsl-verizon.net
    (node name) $k = ABIServer
    ================================================== ======

    ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
    Enter

    > localhost.localdomain

    localhost
    ABIServer
    pool-71-103-120-74.lsanca.dsl-w.verizon.net
    ABIServer.dsl-verizon.net
    [127.0.0.1]
    [pool-71-103-120-74.lsanca.dsl-w.verizon.net]
    [10.0.0.1]
    [71.103.120.74]
    > user@ABIServer:~

    $

    It's identical to yours except the part after ADDRESS TEST MODE.

    Does that help any?

    But, is it too early to make a decision to explain to the PHB that it's
    not worth trying, because of the possibility of lost emails, vs. getting a
    static IP number?

    Thanks,
    Rich


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