Cukunbaba: > What happens if postfix don't get answer from one of rbl lists? > Is there some default timeout and can we changed it?
DNS lookups are made by system library routines. On some systems their retry and timeout behavior is described in the resolver(5) manpage. For a mail flow overview, see http://www.postfix.org/FILTER_README.html#advanced_filter http://www.postfix.org/OVERVIEW.html Wietse