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So, randomly I happened to ping abc.com and found this fascinating:

$ ping abc.com
PING abc.com (199.181.132.250) 56(84) bytes of data.
64 bytes from m.abc.com (199.181.132.250): icmp_req=1 ttl=237 time=90.3 ms
64 bytes from tdl.disneyuniversity.com (199.181.132.250): icmp_req=2 ttl=237 time=89.8 ms
64 bytes from preschooltime.go.com (199.181.132.250): icmp_req=3 ttl=237 time=95.1 ms
64 bytes from futbolpicante.espnfc.com (199.181.132.250): icmp_req=4 ttl=237 time=98.6 ms
64 bytes from www.worldofcars.go.com (199.181.132.250): icmp_req=5 ttl=237 time=86.9 ms
64 bytes from www.verizon.bravesweepstakes.com (199.181.132.250): icmp_req=6 ttl=237 time=87.9 ms
64 bytes from www.directv.bravesweepstakes.com (199.181.132.250): icmp_req=7 ttl=237 time=87.9 ms
64 bytes from manup.abc.com (199.181.132.250): icmp_req=8 ttl=237 time=88.8 ms
64 bytes from m.onemoredisneyday.com (199.181.132.250): icmp_req=9 ttl=237 time=87.5 ms
64 bytes from finance.abc30.com (199.181.132.250): icmp_req=10 ttl=237 time=87.9 ms
64 bytes from finance.abc13.com (199.181.132.250): icmp_req=11 ttl=237 time=88.0 ms
...

In a way it seems similar to load balancing used in forward DNS, except I don't understand how this would be useful.

Is there any practical reason for this or just a consequence of these sites all being hosted behind the same IP address?

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Isn't that forward DNS? Reverse would be if you searched by IP. It doesn't happen when I ping them now. I get the same result repeatedly. Perhaps this has something to do with the way their DNS wildcard works? –  user160910 Apr 19 '13 at 21:12
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3 Answers 3

nslookup 199.181.132.250 shows up witn bunch of non-authoritative answers for different domain names. But my ping doesn't change dynamically as yours.

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It really looks someone just being funny, or server misconfigured or something like that. There are actually that many reverse records.

btw. i suspect this IP might be used to distribute spam and these hostnames are there to confuse filters. (but that is a wild guess)

see:

$ dig 250.132.181.199.in-addr.arpa -t PTR
;; Truncated, retrying in TCP mode.

; <<>> DiG 9.7.3 <<>> 250.132.181.199.in-addr.arpa -t PTR
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33536
;; flags: qr rd ra; QUERY: 1, ANSWER: 195, AUTHORITY: 4, ADDITIONAL: 2

;; QUESTION SECTION:
;250.132.181.199.in-addr.arpa.  IN      PTR

;; ANSWER SECTION:
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.nightofjoy.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.disneyworld.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.mustdodisney.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.disneytheforce.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.onemoredisneyday.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     s.espnradio.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     fb.steelgetsreal.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     my.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     qa.watchdisneyxd.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     qa.watchabcfamily.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     qa.watchdisneyjunior.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     qa.watchdisneychannel.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     uk.disneycareers.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     abc.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     cdn.musiclounge.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     fdj.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     fdj.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     gma.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     hdf.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     hub.disneyuniversity.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     itm.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     lnb.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     sam.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     tdl.disneyuniversity.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     ugc.lionking.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     ugc.marypoppins.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     ugv.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     vpd.disneycruise.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     w88.m.fwfest.waltdisneyworld.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.att.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.cox.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.ttdl.disneyuniversity.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.enter.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.charter.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.directv.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.verizon.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.mediacom.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.adventure.bravesweepstakes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneyhome.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.worldofcars.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneycasting.net.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.donovandecker.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneyroommate.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneycampusrep.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneycollateral.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneyinternsinfo.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.missiontimekeeper.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneycastingscout.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneyimaginations.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneyprogramsblog.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.wdwcollegeprogramecard.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.wdwcollegeprogramecard2.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     www.disneyinternationalepresentation.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     1ext.doit.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     25th.disneystore.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     beta.xgames.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     blog.disneyxd.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     bmoc.abc7chicago.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     doit.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     live.dadt.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     live.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     play.toontown.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     prod.waltdisneystudios.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     ugv2.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     blogs.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     cards.babyzone.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     email.doit.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     email.disneymovieclub.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     espn3.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     games.soapnet.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     manup.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     panam.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     castle.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     comedy.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     espnrf.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     hdfmas.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     health.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     mobile.abcfamily.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     oscars.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     photos.kaboose.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     photos.babyzone.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     search.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     search.video.movies.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     temail.disneymovieclub.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     tienda.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     topics.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     velti2.disneylandsummer.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     workit.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     999test.abcnews.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     account.toontown.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     casting.disneyparks.jobs.
250.132.181.199.in-addr.arpa. 180 IN    PTR     catalog.disneyuniversity.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     clarity.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     culture.disneyuniversity.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.6abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.abc7.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.abc11.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.abc13.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.abc30.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.7online.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.abc7news.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     finance.abc7chicago.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     hotseat.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     missing.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     playdom.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     preview.mydisneyphotopass.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     revenge.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     scandal.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     scrumtv.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     search2.spanish.disneylandsummer.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     theview.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     topics2.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     uplayit.abc7chicago.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     developu.disneyuniversity.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyhd.tv.
250.132.181.199.in-addr.arpa. 180 IN    PTR     polo2011.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     theriver.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     whereami.doit.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     abccomedy.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     helpoffer.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     rugby2011.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     shelterme.6abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     stagepass.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     tenis2011.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     themiddle.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     trongames.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     cougartown.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     devicedata.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneytime.disneyparks.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyvisa.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     experience.disneydestinations.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     happyrides.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     portfolios.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     storefront.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     bodyofproof.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     copavirtual.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     desafioeuro.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyparks.jobs.
250.132.181.199.in-addr.arpa. 180 IN    PTR     familytools.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     glass-house.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     hipcricket2.spanish.disneylandsummer.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     klubpenguin.de.
250.132.181.199.in-addr.arpa. 180 IN    PTR     klubpinguin.de.
250.132.181.199.in-addr.arpa. 180 IN    PTR     musiclounge.abc.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     preolimpico.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     radiodisney.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     suburgatory.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     weatherblog.abc13.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     abcdotcomedy.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     euroquiniela.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     happyendings.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     modernfamily.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     sendtofriend.abcnews.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     desafiofutmex.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     dimgpressroom.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneypackage.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneystudios.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     futbolpicante.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     golesdeeuropa.espnfc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     onceuponatime.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     preschooltime.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     rincontecnico.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     yourcommunity.6abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     desafiopremier.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     phineasandferb.disneymags.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyparksblog.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyvisaperks.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     elmejorejemplar.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     lastmanstanding.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     monstroussummer.disneyparks.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     the-glass-house.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyconnection.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     avalanchesoftware.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     celebritywifeswap.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyhumanrights.org.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneysecondscreen.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     watchdisneychannel.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     hablemosdefutbolmas.espndeportes.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     mickeystrickortreat.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneylearningstudio.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     shanghaidisneyresort.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneystarbuckssurvey.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyworldsvacations.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     wheelchairrentaldisney.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     hyperionbooksforchildren.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     disneyparksstarbuckssurvey.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.abc.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.test.doit.go.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.fwfest.waltdisneyworld.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.abcfamily.com.
250.132.181.199.in-addr.arpa. 180 IN    PTR     m.bostonmed.abcnews.go.com.

;; AUTHORITY SECTION:
132.181.199.in-addr.arpa. 180   IN      NS      sens01.dig.com.
132.181.199.in-addr.arpa. 180   IN      NS      orns01.dig.com.
132.181.199.in-addr.arpa. 180   IN      NS      sens02.dig.com.
132.181.199.in-addr.arpa. 180   IN      NS      orns02.dig.com.

;; ADDITIONAL SECTION:
orns01.dig.com.         257     IN      A       68.71.223.14
sens02.dig.com.         242     IN      A       199.181.135.199

;; Query time: 7 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Fri Apr 19 23:24:14 2013
;; MSG SIZE  rcvd: 5471
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This is used for "forward-confirmed reverse DNS." From Wikipedia

A FCrDNS verification can create a weak form of authentication that there is a valid relationship between the owner of a domain name and the owner of the network that has been given an IP address. While weak, this authentication is strong enough that it can be used for whitelisting purposes because spammers and phishers can not usually by-pass this verification when they use zombie computers for mail spoofing. That is, the reverse DNS might verify, but it will usually be part of an other domain than the claimed domain name.

However, I know of no application that actually looks at more than 1 PTR RR. It could be that Disney has some services that look at more than 1 PTR RR.

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