MoinQ:

ccTLD/tvについて、ここに記述してください。

sakura で使われている from.tv 情報 http://www.enom.com/whois/default.aspx?DomainName=from.tv

/ustream.tv

%dnsq ns tv a.root-servers.net                                                               ~
2 tv:
316 bytes, 1+0+7+9 records, response, noerror
query: 2 tv
authority: tv 172800 NS l5.nstld.com
authority: tv 172800 NS h5.nstld.com
authority: tv 172800 NS g5.nstld.com
authority: tv 172800 NS f5.nstld.com
authority: tv 172800 NS d5.nstld.com
authority: tv 172800 NS c5.nstld.com
authority: tv 172800 NS a5.nstld.com
additional: l5.nstld.com 172800 A 192.41.162.34
additional: h5.nstld.com 172800 A 192.54.112.34
additional: h5.nstld.com 172800 28 \040\001\005\002\010\314\000\000\000\000\000\000\000\002\0004
additional: g5.nstld.com 172800 A 192.42.93.34
additional: f5.nstld.com 172800 A 192.35.51.34
additional: f5.nstld.com 172800 28 \040\001\005\003\324\024\000\000\000\000\000\000\000\002\0004
additional: d5.nstld.com 172800 A 192.31.80.34
additional: c5.nstld.com 172800 A 192.26.92.34
additional: a5.nstld.com 172800 A 192.5.6.34

a5.nstld.com A は別途確認が必要だ。(TTLが300と短い av*.nstld.comに依存するのはw)

$ dnsq a ac1.nstld.com 192.82.133.30

1 ac1.nstld.com:
295 bytes, 1+1+4+8 records, response, authoritative, noerror
query: 1 ac1.nstld.com
answer: ac1.nstld.com 300 A 192.42.173.30
authority: nstld.com 86400 NS av3.nstld.com
authority: nstld.com 86400 NS av1.nstld.com
authority: nstld.com 86400 NS av2.nstld.com
authority: nstld.com 86400 NS av4.nstld.com
additional: av3.nstld.com 300 A 192.82.133.30
additional: av3.nstld.com 300 28 \040\001\005\000\001&\000\000\000\000\000\000\000\000\0000
additional: av1.nstld.com 300 A 192.42.177.30
additional: av1.nstld.com 300 28 \040\001\005\000\001$\000\000\000\000\000\000\000\000\0000
additional: av2.nstld.com 300 A 192.42.178.30
additional: av2.nstld.com 300 28 \040\001\005\000\001%\000\000\000\000\000\000\000\000\0000
additional: av4.nstld.com 300 A 192.82.134.30
additional: av4.nstld.com 300 28 \040\001\005\000\001'\000\000\000\000\000\000\000\000\0000

これがTTL満了になると、どれくらいの影響があるか、考えてみてください。