SMTP fails when email hosted elsewhere

Discussion in 'Email' started by TKStom, Dec 22, 2010.

  1. I setup an account for authentication: [email protected]. Mail for the domain is hosted elsewhere. When the contact form sends mail to an address outside of the domain, it works fine. When the contact form send mail to a valid address - [email protected] - which is hosted on a different service, I get an error message. Apparently SmarterMail thinks it will deliver locally, but sees it doesn't have that account. How can I tell SMTP to just pass the message along?

    The error message is:
    Mailbox unavailable. The server response was: <[email protected]> No such user here

    where [email protected] is the recipient's address, not the authentication address. If I add a BCC to the message, the BCC is received, even though I get this error message. The message to [email protected] is not received.
  2. Ray


    That pretty much has SmarterMail and any mail server works. It will always look internally first before it sends out the email.
    Our mail servers is really not setup as an open SMTP relay server. If you are not using our email server to receive email, I suggest you disable your email account our system and not use our SMTP server to send out email.
  3. There is no option for a "generic" Winhost SMTP server? This seems like a fairly common scenario. I can probably setup an account with the other mail provider, but then there is a connection across the internet, by the webserver, rather than a local connection to an SMTP server.
  4. Ray


    No I'm afraid not. Really, a lot of hosting companies are getting away form open SMTP relay. Its just prone for spamming.
  5. It's not really open if you have to authenticate and/or be on the same network, is it?
  6. Ray


    Well, if you authenticate then you need to setup a local account on the email server. And if you setup an account on the email server it will first look to its local internal list for those email domain name. Unfortunately this is just how email works. The only way to do this is to setup an open smtp relay server where it simply sends out email and it does not have an email account built into it. That is why it is called an open smtp relay server.
  7. What is the server you refer to in this thread:

    Seems like that's a generic SMTP server?

    Isn't there a difference between an open smtp relay server (which is bad) and an smtp server (which, for example, comes with Windows Server)? What I'm talking about is the "open" part - an SMTP server doesn't need to be open, does it? It can still be authenticated or limited to only addresses on your network, right?
    Last edited by a moderator: Oct 14, 2015
  8. Ray

    Ray is the SmarterMail mail server. If you ping your mail server and lets say is using they should both resolve to the same IP address.
    I think you have a perception that the mail server we are using is part of the Windows Microsoft operating system. I'm afraid they're not. SmarterMail is a 3rd party tool we have licensed with SmarterTools.

    I think you maybe thinking of MS Exchange where it authenticates itself with the Windows Access Control List or some kind of user list in the Operating system to help authenticate the relay request. This cannot work on a shared hosting environment because we do not use MS Exchange. Infact MS Exchange is great for a single corporate business because it only has one email domain nae "i.e." but Exchange don't work well when you have thousands of different email domain name. Plus even if we can setup MS Exchange to do this, it will be difficult for a shared hosting company to setup multiple windows accounts to authenticate with MS Exchange for relaying. I can only see all the complexity and labor in keeping and maintaining such a list where you are constantly adding and dropping an account. I suppose if it is a dedicated hosting where you are the only one on the server then it is more feasible to do. But I'm afraid in a shared hosting environment this maybe difficult to implement.

    On the other hand if we do enable the web servers SMTP service then we really do not have to impose SMTP authentication. All we need is a valid hosting account, but that too can be abused. One merely needs to setup an account and send out a large amount of email through the localhost SMTP service. The problem is if it is not authenticated it will be difficult to find who is sending the mass amount of email and we'll have to look at the SMTP log and see if we can find a pattern and narrow down the offending account.
  9. I feel like I've just attended email school...

    Nice work.

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