Hi there, We are a large ISP and we have noticed some Exim implementations issue RCPT TO back to us on our RCPT TO to verify the sender.
They do this by establishing a separate connection to our MX -- presumably as an alternative to SPF -- in order to verify the authenticity of the sender. If this is an Exim feature, where can I get documentation on how this works? I expect this could create a recursive loop if two mail servers that both implement this feature send mail between one another. How is a loop avoided? Are there any blogs, caveates, discussions about this kind of behaviour in general? With kind regards -paul -- ## List details at http://lists.exim.org/mailman/listinfo/exim-dev Exim details at http://www.exim.org/ ##
