Am 01.10.2014 um 19:04 schrieb Ronald F. Guilmette: > I have been thinking of maybe putting up an experimental > anti-spam blocklist server. As far as the client interface, > this would operate in the usual way, i.e. via DNS, just as > all of the current well-known blacklists do. > > Due to the (backend) nature of the thing however, it would > probably only provide service ... initially at least... > from a single machine and a single IP address. > > I am curious what would happen to Postfix clients if they > included references to that in their smtpd_recipient_restrictions, > and if the one and only server for the thing went down for a > time. > > What would happen in such a case? Would inbound e-mail start to > back up horribly, as Postfix waited for DNS responses that were > not forthcoming?
no - no answer is just no answer and mail goes through but why have a single point of failure? just use rbldnsd and rsync it to a second machine - it even reloads changed zones each minute without doing anything, rbldnsd beats out any pther DNS software by it's nature that it was developed for only RBL's and nothing else RBL's in "smtpd_recipient_restrictions" are mostly a bad idea after "Postscreen" was introduced which caches results and can do weighting instead block unconditionally
