Search Again: Re: reverse DNS questions From: Michael Wise Date: Friday, September 5, 2003 Time: 9:02:24 am At 0:06 -0500 9/5/03, Mia's Virtual Post Office wrote: >> >>Several bad assumptions here: >> >>1) That somebody paying an extra 10-20% to have their account >>classifies as a "business" one is any more secure than one who has >>a "residential" one. >> >>2) That SBC "business" DSL customers automatically have an rdns >>suggesting so (they don't) > >They should. If they do not report SBC to ARIN. Show up in Chicago >and ask ARIN why they do not? I create PTR record for every >customer, EVERY CUSTOMER. When we set up a new Wireless customer >their inverse DNS is provisioned before their link is installed. >Its simple, required and extremely important. I'm not sure what would be reported to ARIN. I'm not saying SBC business (or residential, for that matter) DSL IP blocks do not have an rdns...I am saying that the default rdns which does exist doesn't clearly identify, to RR.com's satisfaction, that it is being used for business. Let's take my old "business" Pac Bell DSL block (which SBC still has swipped to my former employer who paid for it): 63.193.99.80/29 Pac Bell Internet Services PBI-NET-7 (NET-63-192-0-0-1) 63.192.0.0 - 63.207.255.255 Wired Magazine SBCIS24627 (NET-63-193-99-80-1) 63.193.99.80 - 63.193.99.87 Now I'll take a look-see at the rdns for the IP my mail server used to operate at, until three months ago: mike@pb:~$ nslookup 63.193.99.85 85.99.193.63.in-addr.arpa name = adsl-63-193-99-85.dsl.snfc21.pacbell.net. RR.com would block mail from that IP, not because it is dynamic (it isn't); not because it or any net block has ever been a spam source (they haven't); and not even because of RR.com's stupid "we-don't-accept-email-from-residential-dsl-addresses" mantra (as that block was business-class DSL. It would be blocked because RR.com cannot tell from looking at the rdns (as if they even bother to look) that it is a "business-class" DSL line. They see *adsl* *dsl* and *pacbell.net" or some combination thereof and it gets blocked. I'm pretty sure they're not blocking all mail coming from machines with *adsl* *dsl* in the rdns, but they definitely do if *pacbell.net* is also in the string. They claim that if a word like *biz* is also in the rdns string, it won't be blocked. I doubt that though. What they really want is for rdns to not contain *adsl* or *dsl* at all....and they state that if the provider will not make that change or delegate reverse authority to do so...then the sender will need to smart host or use the provider's mail server to send any mail to rr.com. You're right...they're completely arrogant. --Mike

Messages In This Thread: Reverse DNS questions by Andrew Murray on Jul 30, 1998 at 6:23:00 pm Re: Reverse DNS questions by Craig Phillips on Jul 31, 1998 at 12:39:00 am Re: Reverse DNS questions by Chris Buxton on Jul 31, 1998 at 6:58:00 am Re: Reverse DNS questions by Mia''s Virtual Post Office on Jul 31, 1998 at 12:23:00 pm Reverse DNS Questions by Mia''s Virtual Post Office on May 27, 1999 at 6:33:00 pm Re: Reverse DNS Questions by Men & Mice Support on May 28, 1999 at 12:21:00 am reverse DNS questions by Hazlitt on Sep 4, 2003 at 6:48:15 pm Re: reverse DNS questions by Michael Wise on Sep 4, 2003 at 7:06:46 pm Re: reverse DNS questions by Len Conrad on Sep 4, 2003 at 7:30:19 pm Re: reverse DNS questions by Michael Wise on Sep 4, 2003 at 7:55:00 pm Re: reverse DNS questions by Jeff Justice on Sep 4, 2003 at 8:28:36 pm Re: reverse DNS questions by Mia''s Virtual Post Office on Sep 4, 2003 at 10:07:17 pm Re: reverse DNS questions by Mia''s Virtual Post Office on Sep 4, 2003 at 10:21:21 pm Re: reverse DNS questions by Jeff Justice on Sep 4, 2003 at 10:46:58 pm Re: reverse DNS questions by Len Conrad on Sep 5, 2003 at 2:57:32 am Re: reverse DNS questions by Kenneth Kirksey on Sep 5, 2003 at 5:20:57 am Re: reverse DNS questions by Michael Wise on Sep 5, 2003 at 9:02:24 am Re: reverse DNS questions by Michael Wise on Sep 5, 2003 at 9:32:15 am Re: reverse DNS questions by Mia''s Virtual Post Office on Sep 5, 2003 at 4:33:53 pm Re: reverse DNS questions by Roland A. Dumas on Sep 6, 2003 at 11:48:53 pm Re: reverse DNS questions by Brian R. Watters on Sep 28, 2003 at 2:36:42 pm