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  • mail deferred for non existing domain

    From Hans Mayer@21:1/5 to All on Tue Mar 7 07:41:40 2023
    Dear Claus, et al,

    we have a strange situation but let me explain the environment.

    hop1 ) we have two incoming SMTP gateways running sendmail 8.15.1 on Solaris these servers are forwarding the incoming mails through the FW to an internal mail-gateway on port 18000 without the domain part in the e-mail. Don't blame me, this wasn't my idea and setup.
    hop2) this is also Solaris on Sparc with sendmail 8.15.2
    this servers accepts emails on port 18000 and forwards it on the same host but different sendmail instance to hop3 listening on port 25 also with sendmail 8.15.2
    hop3 ) this finally delivers to internal Exchange
    hop4 ) MS Exchange

    Now it happens from time to time that we cannot resolve DNS for some certain domain names, primary this happens sometimes for some domains in China or Iran.

    Now following happens. Someone sends an e-mail from outside to one (or more) recipient at us (IIASA) and another recipient at China. Such an e-mail will be accepted by hop1 and 2 but hangs in the queue when it should be forwarded to hop3. I could verify
    the situation sending such an e-mail from my private server. In the mailq for server listening on port 18000 there I see a deferred mail and in the q-file I see the following lines

    H??To: MAYER Hans <hans.mayer@iiasa.ac.at>, echo.noreply@lreis.ac.cn
    H??From: Hans Mayer <ha-mayer@ma.yer.at>
    H??Subject: versuch an lreis.ac.cn

    So my primary question, why is sendmail checking a domain name when it's not responsible at all ?
    And then of course a second question pops up, why is hop1 accepting this e-mail ?

    I am quite sure one needs some more detailed information to give an answer but I am happy to provide you with this.

    Kind regards
    Hans

    --

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Claus =?iso-8859-1?Q?A=DFmann?= @21:1/5 to Hans Mayer on Tue Mar 7 11:19:26 2023
    Hans Mayer wrote:

    So my primary question, why is sendmail checking a domain name when it's not responsible at all ?

    Because it tries to "canonify" them
    (BTW: if the domain does actually not exist then DNS should return
    a permanent error: NXDOMAIN which does not cause a "deferral").

    Look for nocanonify in cf/README and sendmail/TUNING.

    --
    Note: please read the netiquette before posting. I will almost never
    reply to top-postings which include a full copy of the previous
    article(s) at the end because it's annoying, shows that the poster
    is too lazy to trim his article, and it's wasting the time of all readers.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Hans Mayer@21:1/5 to All on Fri Mar 10 02:15:32 2023
    Dear Claus,
    many thanks for your reply. I will try it but currently a modification is hard to test as it works with the old config.

    Kind regards
    Hans

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Otto J. Makela@21:1/5 to All on Mon Mar 13 14:38:02 2023
    A related question: does .REDIRECT co-operate with rewriting?

    I run an email system where clients have entered their email
    addresess for mailing purposes, and there are the standard typo
    squatter domains (like gmail.co), where it'd be nice to rewrite any
    addresses as %1@gmail.com.REDIRECT but this doesn't seem to work?
    --
    /* * * Otto J. Makela <om@iki.fi> * * * * * * * * * */
    /* Phone: +358 40 765 5772, ICBM: N 60 10' E 24 55' */
    /* Mail: Mechelininkatu 26 B 27, FI-00100 Helsinki */
    /* * * Computers Rule 01001111 01001011 * * * * * * */

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Otto J. Makela@21:1/5 to All on Tue Mar 14 15:09:09 2023
    A related question: does .REDIRECT co-operate with rewriting?

    I run an email system for a system where clients have given their email addresess for mailing purposes. There are the standard typo squatter
    domains (like gmail.co), where it'd be nice to rewrite any addresses as %1@gmail.com.REDIRECT instead of holding the message in a mail queue for
    a couple of days and only then producing a bounce.

    I've tried adding gmail.co into virtuserhosts and the above rewrite
    rule into virtusertable. Unfortunately, .REDIRECT doesn't seem to work
    within this context, or did I make some silly typo somewhere?
    --
    /* * * Otto J. Makela <om@iki.fi> * * * * * * * * * */
    /* Phone: +358 40 765 5772, ICBM: N 60 10' E 24 55' */
    /* Mail: Mechelininkatu 26 B 27, FI-00100 Helsinki */
    /* * * Computers Rule 01001111 01001011 * * * * * * */

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Claus =?iso-8859-1?Q?A=DFmann?= @21:1/5 to Otto J. Makela on Sat Mar 18 01:53:28 2023
    Otto J. Makela wrote:

    I run an email system for a system where clients have given their email addresess for mailing purposes. There are the standard typo squatter
    domains (like gmail.co), where it'd be nice to rewrite any addresses as %1@gmail.com.REDIRECT instead of holding the message in a mail queue for
    a couple of days and only then producing a bounce.

    Why does the mail stay in the queue? gmail.co does resolve. right?

    If you know addresses are "invalid" why don't you reject them
    directly, e.g., using
    mailertable Include a "mailer table" which can be used to override
    ....
    error:code message
    error:D.S.N:code message
    will give an error message with the indicated SMTP reply
    code and message, where D.S.N is an RFC 1893 compliant
    error code.

    Anyway, if you want to figure out whether ".REDIRECT" works
    in your setup, use sendmail -bt and something like
    3,0 user@gmail.co
    /tryflags er
    /parse user@gmail.co

    If that doesn't give you a clue where the problem is, post the
    output here and explain which result(s) you expect(ed).


    --
    Note: please read the netiquette before posting. I will almost never
    reply to top-postings which include a full copy of the previous
    article(s) at the end because it's annoying, shows that the poster
    is too lazy to trim his article, and it's wasting the time of all readers.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)