On 01/07/2010 01:50 PM, Paul Sheer wrote: > 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?
http://exim.org verify sender /callout > > 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? Do the sender-verify only for non-null FROM, and using a null FROM - just like emitting a bounce. Unless you're Microsoft. > > Are there any blogs, caveates, discussions about this kind of behaviour in > general? Some people think that sender-verifies are evil. Google. Cheers, Jeremy -- ## List details at http://lists.exim.org/mailman/listinfo/exim-dev Exim details at http://www.exim.org/ ##
