- /* If an early command (up to and including MAIL FROM:<>) was rejected,
- there is no point carrying on. The callout fails. */
-
- if (cache_record->result == ccache_reject)
+ /* In most cases, if an early command (up to and including MAIL FROM:<>)
+ was rejected, there is no point carrying on. The callout fails. However, if
+ we are doing a recipient verification with use_sender or use_postmaster
+ set, a previous failure of MAIL FROM:<> doesn't count, because this time we
+ will be using a non-empty sender. We have to remember this situation so as
+ not to disturb the cached domain value if this whole verification succeeds
+ (we don't want it turning into "accept"). */
+
+ old_domain_cache_result = cache_record->result;
+
+ if (cache_record->result == ccache_reject ||
+ (*from_address == 0 && cache_record->result == ccache_reject_mfnull))