The Community Forums

Interact with an entire community of cPanel & WHM users!
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

catch-all changes in 11

Discussion in 'General Discussion' started by ike, Jul 24, 2007.

  1. ike

    ike Well-Known Member

    Joined:
    Apr 22, 2003
    Messages:
    47
    Likes Received:
    0
    Trophy Points:
    6
    Ive noticed that the :blackhole option is missing in the new cpanel catch-all area. is it somewhere else i havent seen or is it just gone? Has something else replaced it?
     
  2. freedman

    freedman Well-Known Member

    Joined:
    Feb 13, 2005
    Messages:
    312
    Likes Received:
    1
    Trophy Points:
    18

    you're not supposed to use :blaickhole: anymore, it causes bad things from what I remember.
    use :fail:
    instead
     
  3. mtindor

    mtindor Well-Known Member

    Joined:
    Sep 14, 2004
    Messages:
    1,281
    Likes Received:
    37
    Trophy Points:
    48
    Location:
    inside a catfish
    cPanel Access Level:
    Root Administrator
    Freedman is right.

    Assume you set an email address up to use :blackhole:

    If an email is sent to that address, the server accepts it and then generates a bounce. If the sender address was a forged sender address, an innocent party who never actually sent you email suddenly gets a bounce message. This is 'backscatter'. It can cause many mail systems to blacklist the mail server you are using. It is not net-friendly.

    Assuming you set an email address up to use :fail:

    If an email is sent to that address, the server _rejects_ it during SMTP phase (rather than accepting it, processing it, and bouncing it). This stops your server from sending back bounces to forged sender addresses. And with :fail: there is also much lower resource usage on your server since it rejects during SMTP instead of accepting/processing/bouncing.

    Let's paint a picture about :blackhole: - Let's say you set up the domain's default address to be :blackhole:, then a spammer could send to 1000 messages to nonexistent email addresses in your domain. Each of those messages could be from different forged senders (which would be the case with most spam and viruses). Your server would have to accept all 1000 of those emails, process them, then bounce them back to the forged sender (who never initiated an email conversation with you to begin with). So your server has to handle the incoming mail processing load for those 1000 messages, and then there are 1000 angry people on the internet who received bounce notifications for email that they never sent.

    Mike
     
    #3 mtindor, Jul 24, 2007
    Last edited: Jul 24, 2007
  4. sparek-3

    sparek-3 Well-Known Member

    Joined:
    Aug 10, 2002
    Messages:
    1,384
    Likes Received:
    23
    Trophy Points:
    38
    cPanel Access Level:
    Root Administrator
    I don't think :blackhole: sends bounce message. It basically just stores the message into /dev/null.

    :blackhole: shouldn't be used because the message is still processed, its just not stored anywhere so it does waste a few CPU cycles. Probably not really enough to really matter, but at the same time why waste CPU cycles anyway? The default box should be set to :fail:

    Unless I am mistaken, I don't think :blackhole: will send a bounce notification.
     
  5. mtindor

    mtindor Well-Known Member

    Joined:
    Sep 14, 2004
    Messages:
    1,281
    Likes Received:
    37
    Trophy Points:
    48
    Location:
    inside a catfish
    cPanel Access Level:
    Root Administrator
    Ok, you may very well be right - I couldn't remember the 'other' option that you wouldn't want to use. Maybe they used to have an option to 'bounce' or something and that's what i was thinking.

    When I was writing it, blackhole I knew would dev/null it and so I was thinking that there probabyl would be no bounce, but dummy me I went ahead and typed it out against my own reservations of doing so rofl.

    You got me on that one :)

    Mike
     
  6. freedman

    freedman Well-Known Member

    Joined:
    Feb 13, 2005
    Messages:
    312
    Likes Received:
    1
    Trophy Points:
    18
    I believe you are correct. it DELIVERS the message into a blackhole (/dev/null).

    and the problem is that, yes, the message appears to be delivered.
    Some server conscious spammers do use SMTP failures to prune their email lists.
    if the server doesn't indicate a failure, they think it's a good email address and will continue delivering mail to it which means, not only are you wasting cycles processing and disgarding this message, but you're inviting more in the future.

    the theory is, even spammers have to prune their lists at some point or they wouldn't be able to send their lists out in any reasonable (to them) amount of time, so getting them to realize an email is invalid might get them to leave you alone altogether....in addition, some of them use name spinners and will 'test' email addresses for the purpose of including in spam lists.
    If the tests fail, you may never hear from them again.
     
  7. sparek-3

    sparek-3 Well-Known Member

    Joined:
    Aug 10, 2002
    Messages:
    1,384
    Likes Received:
    23
    Trophy Points:
    38
    cPanel Access Level:
    Root Administrator
    I think a very long time ago, this is what the :fail: option used to do. It used to accept the message and then send back a bounce message saying that the address did not exist. This would be a bad set up, and if that were the case then :blackhole: would be a much better solution.

    The functionality of :fail: was changed a few years ago to where it checked itself after the RCPT TO: stage in an SMTP transaction and would deny a transaction at this point if :fail: were used and the address did not exist.

    So in short, anybody that is reading this now, :fail: is what you want to use. It does not send a bounce message from your server.
     
  8. dexus

    dexus Well-Known Member

    Joined:
    Jan 14, 2006
    Messages:
    169
    Likes Received:
    0
    Trophy Points:
    16
    cPanel Access Level:
    Root Administrator
    I don't know what gave you such idea, :fail: will always bounce a message with error 550.
     
  9. rs-freddo

    rs-freddo Well-Known Member

    Joined:
    May 13, 2003
    Messages:
    832
    Likes Received:
    1
    Trophy Points:
    18
    Location:
    Australia
    cPanel Access Level:
    Root Administrator
    cp11 still does have blackhole and it's under "advanced" or "other" or some such. Yes, black hole is useful. Remember in cpanel you can setup exim to refuse mail that doesn't have a valid sender - guess what :fail: is not a valid sender, but :blackhole: is. So, yes, blackhole does have it's uses - but it's better to use fail except where you need to send out mail with a noreply email address (and then mark the email that a reply to this email will go nowhere).
     
  10. cPanelNick

    cPanelNick Administrator
    Staff Member

    Joined:
    Mar 9, 2015
    Messages:
    3,426
    Likes Received:
    2
    Trophy Points:
    38
    cPanel Access Level:
    DataCenter Provider
    Yes but your server won't generate the bounce, the sending server will
     
  11. dexus

    dexus Well-Known Member

    Joined:
    Jan 14, 2006
    Messages:
    169
    Likes Received:
    0
    Trophy Points:
    16
    cPanel Access Level:
    Root Administrator
    Yes, that is true :)
     
  12. ike

    ike Well-Known Member

    Joined:
    Apr 22, 2003
    Messages:
    47
    Likes Received:
    0
    Trophy Points:
    6
    thanks for that guys. :fail: ftw :) explains why its more recommended that discard :blackhole:
     
Loading...

Share This Page