Hi All,

Myself and a friend have our own small IT business; we mainly design and build web sites for other small businesses.

One of the things we would like to offer to clients is the ability to relay email addressed to their company's domain to their own personal email address (either web-based, or hosted by their ISP).

Now, clearly there is a risk of our mail relay being marked as "open", and therefore becoming black listed as a source of spam. Not something that we want to happen!

Has anyone any experience in setting up such a system? I understand how I would go about configuring an MTA like Postfix or Sendmail to perform such a task, but I'm unsure how I would ensure that relayed mail is delivered and we're not labeled as spammers.

I did wonder if perhaps the "mail forwarding" options in a mail server like Zimbra would get around the issue by forwarding on messages inline or as attachments within new emails (so the messages would appear to be from the account hosted on our server).

Look forward to hearing your responses!

Thank you in advance.

Cheers,

Pete

You certainly don't need an open relay to do what you are suggesting. How many accounts are you talking about?

It would only be a couple at first, but obviously there could be a possibility of more later. It all depends on how many of our clients would be interested in the service.

Thanks,

Pete

You could just do the using basic aliases. I assume you are hosting their email for them generally?

Thanks for the response, it's most appreciated.

In answer to your query, you are correct; the MX records for their domain point to our servers.

Will local aliases change the "from" address of the email? I'm not sure if this will get around the issue of relayed mail being labelled as spam by ISPs and email hosts.

Cheers,

Pete

If you define an alias of

someuser : someotheruser@example.com

you aren't relaying, you are effectively forwarding. Why do you expect this to be labeled spam?

When I set up something similar in the past, some messages were rejected by an ISP (BT in this case), because they were seeing messages directed to one of their customers' email addresses, but with a different "to" address to the recipient.

This was implemented using "distribution-list" functionality in the software I was using. Essentially, there wasn't a local mailbox for the user, instead their email was redirected by the MTA as soon as it was received.

I apologise for not being clear enough before, thank you for persevering with me!

Cheers,

Pete

set up a sendmail and use it as a smtp auth client. ie... configure smartrelay , so that ur MTA only forwards it to a legitamate MTA. so ur MTA doesnt get blacklisted.

Thanks for the info!

Do you have any recommendations for services to use?

I have used AuthSMTP in the past, but that requires that you register all email addresses that you will be sending email from. This is something that isn't possible if I'm setting up a distribution list for a client.

Cheers,

Pete