The Exclaimer Community

Hi all. We have recently started using the anti spam section of Disclaimer and I have a question.

Like many smaller organisations, our email is delivered to a smart host at our ISP. Our server (Exchange 2003 on SBS2003) regularly polls the ISP's server for new mail by issuing ETRN requests.

Emails coming from external senders whose domains have properly configured SPF records are being rejected because our ISP's smarthost is not authorised to send email for that domain.

Is there any way round this without losing the benefits of SPF filtering?

Cheers

Ed

You must add your ISP's mailhost subnet into the "Relay Servers" section in the DNS tab of the Advanced Settings dialog. The problem is that from a logical point-of-view, your anti-spam is not being processed at your infrastructure boundary.

One of the most critical pieces of information for Anti-spam is the IP address of the client, but this information is not readily accessible if your ISP is handling your incoming email. Fortunately, the IP address is embedded in a Received: header of the message and Exclaimer can extract this, but will only do so if you explicitly state that you trust your ISP not to spam you to oblivion.

The Relay Servers only handles IP addresses, these can be specified using CIDR notification, e.g. 1.2.3.4/24.

Thanks Gary, I'll try that and see how it goes.

 Cheers

Ed