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:fail: = reply to sender?

Discussion in 'General Discussion' started by mealto, Jun 17, 2008.

  1. mealto

    mealto Well-Known Member

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    Inside WHM >> Tweak Settings, one can set catchall default accounts to fail. In an article by configserver

    http://www.configserver.com/free/fail.html

    There is a mention that no reply is sent to the user if fail is chosen.

    But inside cPanel >> Default Address, it says this:

    "Discard with error to sender (at SMTP time)"
    "Failure Message (seen by sender): No such person at this address"

    So when WHM is set to fail, does the sender receive a reply?
     
  2. mealto

    mealto Well-Known Member

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    On another note, I believe inside cPanel (user account) itself, there was a way to set blackhole or fail. Has this option been removed in version 11?
     
  3. sparek-3

    sparek-3 Well-Known Member

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    Discard at SMTP time is the same thing as :fail:

    The error message that is sent is sent to the sender server. You have to understand how an SMTP transaction takes place. After a server sends the RCPT TO command when it is connected to your mail server, one of two things is going to happen. Either that address exists on the server, in which case the mail transaction is carried on. If the address does not exist (meaning your default address has to be set to :fail: or to the Discard setting as described above) then your server sends back a 550 error. The sending server, the server connecting to your server then knows that the address that is trying to be sent to does not exist and stops the connection. Along with this 550 error you can send an error message. This is what the Failure Message textbox is for. With it you can send a simple message to the sending server saying why the 550 error was encountered. So instead of just a simple 550 error you can configure your account to reject the message with "550 No such address here" which is a bit more descriptive.

    Now whether or not if this message actually gets back to the person that was trying to write you depends on how the sending server handles this. Your server is not sending back an e-mail message, all it is sending is an error during the SMTP transaction process. The sending server (the one that is connecting to your server during this SMTP transaction) would be responsible for sending a bounce message back to the sender. This may or may not happen depending on how it is configured. This bounce message may or may not include the error message "No such address here", the sending server may just send a message back to the sender that says the message could not be sent to the recipient.

    Generally you want this error message to be short because a lot of mail servers (if they do send this error message back with the bounce message to the sender) will truncate the error message after so many characters.
     
  4. mealto

    mealto Well-Known Member

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    ok, sounds like fail is the better blackhole. So how do we set things up inside whm + cpanel?

    Inside WHM >> Tweak Settings, looks like we can choose fail for new accounts.

    Inside cPanel >> default address, looks like version 11 has bought some changes and the blackhole option is no longer available. If memory serves, I believe this option was available in older versions but I am unable to locate it now. How do we set things up in Version 11 so that we have properly enabled fail?

    Maybe this is fail: Discard with error to sender (at SMTP time)
    And this is blackhole: Discard (Not Recommended)

    Does that sound right?
     
  5. sparek-3

    sparek-3 Well-Known Member

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    That is correct.
     
  6. thewebhosting

    thewebhosting Well-Known Member

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    If you wish to disable catch all address then just set default address to :blackhole:
     
  7. sparek-3

    sparek-3 Well-Known Member

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    If you use :blackhole: (or Discard (Not Recommended) in the control panel) then if a spammer brute forces random e-mail addresses on your domain then the server is going to expend a lot of power just dealing with those messages. Using :blackhole: the server processes the message just as it were if it were going to deliver the mail to a regular mail account on the server, except the very last step, the step where a message is usually delivered to a mail account, the message is sent to /dev/null which is that endless oblivion where things go and are never seen again.

    So if you are using :blackhole: for your default address and a spammer starts sending messages to random e-mail addresses on your account (usually they fake the from address of one of an e-mail address on your domain, meaning that you would receive a lot of bounce NDR messages) then expect to see a sharp increase in load average as your server will have to deal with the processing of these messages.

    This is why :fail: (Discard with error to sender (at SMTP time) in the control panel) is the better option. The server stops processing after it receives a RCPT TO that does not exist, no data is passed through the server and processed for this message.
     
  8. mealto

    mealto Well-Known Member

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    We are suing fail at the moment and using gmail to send to an invalid email address results in a bounce back (Undeliverable Bounce). Is this because our server is setup to do this or is this controlled by the sender account (Gmail in this case)?

    The only issue I would think can result from using fail is that if too many bounces happen from spammers using your reply to in the domain, is the potential to get blacklisted. Any thoughts on this issue?
     
  9. cPanelDavidG

    cPanelDavidG Technical Product Specialist

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    Fail uses a SMTP error code, meaning it's not really your mail server generating the bounces but rather the server sending to your server... meaning the load on your server is minimal.
     
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