I set smtp_active_hostname based on the if being used. This can result in
a range of hostnames, sometimes public (eg. stum.gink.org), sometimes
private (eg. stum.ccl4) etc.
When a message comes in on a "private" if (and a private active_hostname
is thus derived) exim proceeds to do a sender verify.
It uses this private smtp_active_hostname during the callout, instead of a
public one which would normally be derived from the if that the callout is
performed on.
I've noticed some (well, one) system get upset by this and temporarily
reject the callout RCPT because the HELO response was not a valid public
hostname.
Can anyone see a way around this, apart from entirely dumping the idea of
setting smtp_active_hostname based on if ?