rDNS
Mark Andrews
marka at isc.org
Fri Jan 20 23:36:44 UTC 2017
In message <bed324186eba4d68a4fbf4513747edbd at mxph4chrw.fgremc.it>, "Darcy Kevin (FCA)" writes:
> I think the ISP may have done something untoward with 87.233.202.162.in-addr.arpa, since I'm
> getting a NODATA response for that name, from the 233.202.162.in-addr.arpa zone, most probabl
> y because it's an empty non-terminal. But what would be under that, and why?
They just haven't put in a CNAME for the broadcast address.
; <<>> DiG 9.12.0-pre-alpha+hotspot+add-prefetch+marka <<>> 87.233.202.162.in-addr.arpa ptr
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 57508
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: ca17d311c21b67e97ff0dfc358829ec97d7d5f968d33a429 (good)
;; QUESTION SECTION:
;87.233.202.162.in-addr.arpa. IN PTR
;; AUTHORITY SECTION:
233.202.162.in-addr.arpa. 3583 IN SOA ns1.swbell.net. postmaster.swbell.net. 2016061700 10800 900 604800 3600
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Sat Jan 21 10:35:37 EST 2017
;; MSG SIZE rcvd: 145
Mark
> - Kevin
>
>
> -----Original Message-----
> From: bind-users [mailto:bind-users-bounces at lists.isc.org] On Behalf Of Mark Andrews
> Sent: Friday, January 20, 2017 3:55 PM
> To: bind-users at isc.org
> Subject: Re: rDNS
>
>
> You have the netblock 162.202.233.80-162.202.233.87 (162.202.233.80/29).
>
> When software performs a reverse lookup it constructs a DNS name from the address like 80.233
> .202.162.in-addr.arpa. Now as the netblock is not a full /24 you either have to create 8 zon
> es, one for each PTR record, or provide records at those names which map the lookups to new n
> ames. The later is what has been done here.
> The technique is described in RFC 2317.
>
> ATT has delegated a zone for the first address in the address block to you. That zone is cal
> led 80.233.202.162.in-addr.arpa. It has then added CNAME records to map lookups for the rest
> of the address in your address block into this zone.
>
> e.g.
>
> 81.233.202.162.in-addr.arpa. CNAME 81.80.233.202.162.in-addr.arpa.
> ...
> 86.233.202.162.in-addr.arpa. CNAME 86.80.233.202.162.in-addr.arpa.
>
> The 80.233.202.162.in-addr.arpa zone should look like this.
>
> $TTL 1h
> @ SOA ns1.archaxis.net. me.archaxis.net. (
> 2017012002 ; Serial
> 1h ; Refresh
> 1h ; Retry
> 4w ; Expire
> 1h ) ; Negative cashing TTL
> NS ns1.archaxis.net.
> NS ns2.archaxis.net.
> PTR network.archaxis.net.
> 81 PTR alpha.archaxis.net.
> 82 PTR bravo.archaxis.net.
> 87 PTR broadcast.archaxis.net.
>
> I increased the expire field to 4 weeks as it was way too small.
> Note the reverse for 162.202.233.80 is NOT mapped to a new name so the PTR record for that ad
> dress is at the zone's apex. As all the records had a TTL of 1 hour I set the default TTL to
> that value and removed the per record setting of the TTL. I also removed the class field as
> that is inherited from the zone's declaration.
>
> Don't forget to bump the zones serial when you install it.
>
> Once you have the above sorted out and have tested it. You now need to slave the zone 233.20
> 2.162.in-addr.arpa as that contains the CNAME records. ATT should allow you to transfer it.
> If they don't find a ISP that knows what they are doing. You need a local copy of the zone
> so that when you link goes down you can still do reverse lookups.
>
> zone "233.202.162.in-addr.arpa" {
> type slave;
> masters { 151.164.1.1; };
> file "233.202.162.in-addr.arpa";
> };
>
> Mark
>
> In message <20170120162146.GA14356 at fantomas.sk>, Matus UHLAR - fantomas writes:
> > On 20.01.17 09:57, Ron Wingfield wrote:
> > > I am having difficulty configuring reverse DNS. This has been a
> > problem
> > > for over a year between my server(s) and my ISP, AT&T. Specifically, I
> > > cannot eMail to any recipient that requires rDNS verification, e.g.,
> > > SBCglobal.net, Comcast.net, or AOL. Very frustrating.
> >
> > > . . .why shouldnt this point to my server, 162.202.233.81 and not
> > > AT&Ts?
> >
> > because reverse domains are also tracked from the DNS root:
> >
> > 233.202.162.in-addr.arpa. 7200 IN SOA ns1.swbell.net.
> > postmaster.swbell.net. 2016061700 10800 900 604800 3600
> >
> > 81.233.202.162.in-addr.arpa. 7200 IN CNAME
> > 81.80.233.202.162.in-addr.arpa.
> >
> > > I have coded my BIND 9 in-addr.arpa zone file as follows:
> > >
> > > $ORIGIN 233.202.162.in-addr.arpa.
> >
> > stop defining $ORIGIN in zone file. the $ORIGIN is taken from named "zone"
> > statement.
> >
> > According to those above you have to configure zone
> > 80.233.202.162.in-addr.arpa.
> > and adk swbell.net to fetchit from you.
> >
> > > $TTL 3h
> > > @ IN SOA ns1.archaxis.net. me.archaxis.net. (
> > > 2017012002 ; Serial
> > > 1h ; Refresh
> > > 1h ; Retry
> > > 1h ; Expire
> > > 1h ) ; Negative cashing TTL
> > >
> > > 3600 IN NS ns1.archaxis.net.
> > > 3600 IN NS ns2.archaxis.net.
> > >
> > > 80 3600 IN PTR network.archaxis.net.
> > > 81 3600 IN PTR alpha.archaxis.net.
> > > 82 3600 IN PTR bravo.archaxis.net.
> > > 87 3600 IN PTR broadcast.archaxis.net.
> > >
> > > What is wrong? Is this my problem, or with AT&T?
> >
> >
> >
> > --
> > Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
> > Warning: I wish NOT to receive e-mail advertising to this address.
> > Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
> > Spam is for losers who can't get business any other way.
> > _______________________________________________
> > Please visit https://lists.isc.org/mailman/listinfo/bind-users to
> > unsubscribe from this list
> >
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>
> --
> Mark Andrews, ISC
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742 INTERNET: marka at isc.org
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--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka at isc.org
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