Charlie Brady wrote:
On Wed, 29 Jul 2009, Larry Nedry wrote:
Hi All,
The require_resolvable_fromhost plugin returns DENYSOFT when a host doesn't
resolve. This makes sense with a well behaved host. But I've noticed that
some hosts that don't resolve will continuously retry and never seem to
disconnect. Sometimes this goes on for days.
Do they really fail to disconnect *and* continuously retry? That
combination seems umlikely to me.
I wonder how long ago that observation was made. There's no reason to
think that this bit of strangeness would have much of a correlation with
non-resolving froms domains.
The issue is far more likely to be _how_ the email is rejected.
The only "true" (as in long-term continuous retry) woodpeckering I've
ever seen was an old version of Exchange (around Exchange 5) that took a
5xx after DATA to mean "retry ASAP", without necessarily dropping the
connection.
We've always done 5xx after DATA (over a decade), and haven't seen any
post-DATA-5xx woodpeckers for quite a while.
[A few that might try 5-15 times, but no worse than that.]
It _could_ be that rejecting at MAIL FROM is the problemmatic bit. Try
delaying the DENYSOFT/DENYSOFT_DISCONNECT to the RCPT TO hook.
