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Fowarded Emails Rejected

Discussion in 'E-mail Discussions' started by docbreed, Apr 26, 2006.

  1. docbreed

    docbreed Well-Known Member

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    I've been running into an issue and hoping someone might be able to point me into the right direction.

    Alot of our clients have emails setup example: info@domain.com and have them redirecting to some other domain or even there isp's email account. Which is wonderful and great. But the past few months issues have been getting worse. I've been recieving alot mail rejects.
    orig sender - test@somedomainwedonthost.com
    sends to - info@domainihost.com
    fowards to - client@verizoznn.net

    But it comes back from verizoznn.net pretty much saying rejectted simply because im not sole hoster of somedomainwedonthost.com

    Anyone follow? Now this doesn't happen in all cases but I am seeing more and more of this reverse check security. Is there any way to make this fowarded email in the header send correctly? Example : FROM: info@domainhost.com and in SUBJECT: fowarded from or something that will work?

    --Jeremy
     
  2. sparek-3

    sparek-3 Well-Known Member

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    I have seen this issue and there really just is not a solution to this, short of not allowing the user to forward the e-mail. Generally, forwarding e-mail off of your server is a bad idea. This is a point that I have been trying to stress throughout the past few months. If you host a domain on your server, named yourdomain.com, and the owner of that domain wants to use e-mail addresses for yourdomain.com, then really they should set up mail accounts (POP or IMAP) for those e-mail addresses. This particular issue that you have noted raises its head when users start forwarding mail to a 3rd party e-mail service.

    What happens is a spammer will use a fake From address and send to a domain that you host. Using your example, suppose a user has the following set up on your server:

    info@domainihost.com => client@verizon.net

    so that mail that is sent to info@domainihost.com actually forwards to client@verizon.net.

    A spammer will fake their address, for example a from address of doesnotexist@yahoo.com. So the trace of the spam message goes:

    doesnotexist@yahoo.com -> info@domainihost.com -> client@verizon.net

    The message is sent out from a server somewhere, sent to info@domainihost.com. Your server accepts the message and then attempts to send it to client@verizon.net. However, verizon.net rejects this message, why they reject this message is really just up to them, but they likely have something in place that checks a message to see if it is spam and if it is, it rejects it. So verizon.net rejects the message, and never accepts it. So your server can never deliver the message to client@verizon.net. Your server then attempts to send a message back to doesnotexist@yahoo.com saying that it cannot deliver the message. But again, doesnotexist@yahoo.com is an e-mail address that does not exist, so this failure message just continues to set on your queue until its retry eventually times out.

    As more and more third party e-mail services (verizon, AOL, Yahoo, Hotmail, etc) block more and more messages, this is becoming more and more of a problem. The issue just really comes down to, end users need to set up mail accounts on your server instead of depending on forwarding those messages to another e-mail service. If users do not want to do this or do not feel comfortable using an e-mail client and prefer the offerings of those specific e-mail services, then they should have users write them directly at those addresses.

    In the above example, if the spammer had been writing client@verizon.net, then the message would get rejected again, but instead of your server having to deal with the failure notices, the spammer's outgoing mail server would have this build up of failure messages that would need to be addressed.

    Hope this helps.
     
  3. docbreed

    docbreed Well-Known Member

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    This is exactly whats happening...


    I think itz great that more isp's are blocking port 25 and daemons are reverse checking. For one it prevents a client w/ a virus that sends mass email. And second those Freinds(web hacks) that likes to use scripts and what not to mass email phony emails.. But I guess im not totally shocked by all this however we dont see news articles or information released about these actions taking place which delivers hours of our time tring to figure these issues out. I still want to say there has got to be a way to when fowarding that the mail header can be changed in our situation.

    Till then is there a nice cpanel/whm way to disable the fowarding feature w/ in cpanel?
     
    #3 docbreed, Apr 26, 2006
    Last edited: Apr 26, 2006
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