> Doug Barton <mailto:do...@dougbarton.us> > Thursday, October 30, 2014 9:00 PM > > > Of course not, but it is one that the ISP makes, and that distinction > is useful to the anti-spam folks. IETF should not be making judgements as to what an ISP will value, because not all ISP's behave as you described.
also, it's useless to the anti-spam folks. right now the massively faked and manufactured PTR RR's coming from almost all last-mile providers for about half of all the IPv4 address space that's reachable, has to be laboriously cataloged so that it can be ignored. that is, the lack of a PTR suggests that a device ought not be initiating TCP/25 outside its local network. (this is an observation of how the anti-spam folks, including myself, behave; it is not a recommendation.) knowing this, last-mile providers foolishly and bizarrely create hundreds of millions of PTR RR's that have no value whatsoever since they simply encode the IP address in ASCII and add the ISP's ".foo.net" suffix. knowing this, the anti-spam folks make lists of these manufactured patterns so that (and ONLY so that) they can pretend they do not exist. i suggest an efficiency improvement: don't manufacture these PTR's in the first place. let last-mile devices be PTR-free. signal to anti-spam folks, such as myself, by this method, that these are not real "hosts" and should not be participating in what were once considered end-to-end protocols, such as off-network SMTP. internet service != internet access. can we make that taxonomy explicit, and stop equivocating? Oct 31 00:59:29 ss postfix/postscreen[3912]: NOQUEUE: reject: RCPT from [59.55.248.215]:2294: 550 5.7.1 Service unavailable; client [59.55.248.215] blocked using b.barracudacentral.org; from=<sabrina.g...@yahoo.com>, to=<wsksc...@mibh.com>, proto=ESMTP, helo=<yahoo.com> 215.248.55.59.in-addr.arpa. 69668 IN PTR 215.248.55.59.broad.ja.jx.dynamic.163data.com.cn. ;; Received 106 bytes from 202.101.226.68#53(ns.jxjjptt.net.cn) in 162 ms -- Paul Vixie
_______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
