download.microsoft.comの名前解決に関して。

先日の日記(http://d.hatena.ne.jp/xanthus/20080219/p1)でコメントで教えて貰った(http://d.hatena.ne.jp/memecomputing/20080219#p3)んですが、download.microsoft.comのDNSの設定がだいぶひどいｗ
ウィンドウズのコマンドラインから普通にnslookupを使うだけだとわからなかったんですが、別名(CNAME)の連鎖の嵐。なんだこりゃ。
nslookupのd2コマンドを利用するとウィンドウズでも以下のように情報がわかる。

c:\>nslookup
Default Server:  wingate.server.co.jp
Address:  192.168.10.2

> set d2
> download.microsoft.com
Server:  wingate.server.co.jp
Address:  192.168.10.2

------------
SendRequest(), len 40
    HEADER:
        opcode = QUERY, id = 2, rcode = NOERROR
        header flags:  query, want recursion
        questions = 1,  answers = 0,  authority records = 0,  additional = 0

    QUESTIONS:
        download.microsoft.com, type = A, class = IN

------------
------------
Got answer (256 bytes):
    HEADER:
        opcode = QUERY, id = 2, rcode = NOERROR
        header flags:  response, want recursion, recursion avail.
        questions = 1,  answers = 8,  authority records = 0,  additional = 0

    QUESTIONS:
        download.microsoft.com, type = A, class = IN
    ANSWERS:
    ->  download.microsoft.com
        type = CNAME, class = IN, dlen = 34
        canonical name = download.microsoft.com.nsatc.net
        ttl = 2739 (45 mins 39 secs)
    ->  download.microsoft.com.nsatc.net
        type = CNAME, class = IN, dlen = 20
        canonical name = main.dl.ms.akadns.net
        ttl = 599 (9 mins 59 secs)
    ->  main.dl.ms.akadns.net
        type = CNAME, class = IN, dlen = 7
        canonical name = intl.dl.ms.akadns.net
        ttl = 299 (4 mins 59 secs)
    ->  intl.dl.ms.akadns.net
        type = CNAME, class = IN, dlen = 12
        canonical name = dl.ms.d4p.net
        ttl = 299 (4 mins 59 secs)
    ->  dl.ms.d4p.net
        type = CNAME, class = IN, dlen = 22
        canonical name = dl.ms.georedirector.akadns.net
        ttl = 4002 (1 hour 6 mins 42 secs)
    ->  dl.ms.georedirector.akadns.net
        type = CNAME, class = IN, dlen = 17
        canonical name = a767.ms.akamai.net
        ttl = 2738 (45 mins 38 secs)
    ->  a767.ms.akamai.net
        type = A, class = IN, dlen = 4
        internet address = 203.179.83.12
        ttl = 19 (19 secs)
    ->  a767.ms.akamai.net
        type = A, class = IN, dlen = 4
        internet address = 203.179.83.13
        ttl = 19 (19 secs)

------------
Non-authoritative answer:
Name:    a767.ms.akamai.net
Addresses:  203.179.83.12, 203.179.83.13
Aliases:  download.microsoft.com, download.microsoft.com.nsatc.net
          main.dl.ms.akadns.net, intl.dl.ms.akadns.net, dl.ms.d4p.net
          dl.ms.georedirector.akadns.net

WinGateを通すとdownload.microsoft.comからダウンロードできない件はこれが原因のような気がする。
ただし、DNSリゾルバのログ見ると解決してるような･･･気もするんだけど。

ログより抜粋
Request:	request [02082008] A lookup "a767.ms.akamai.net."
Debug:	selected 192.168.10.2 <IP helper> for request [02082008]<1> (best looking)
Debug:	request [02082008](ID 5184) sent to 192.168.10.2 <IP helper> (36 bytes)
Debug:	useful response [02082008](ID 5184) (0.00s)

うーん、WinGateかDNSかその両方の組み合わせでdownload.microsoft.comの名前解決に失敗してるっぽい。
とりあえずhostsファイルに以下の行を追加して解決した。

203.179.83.12      download.microsoft.com

DNS意味ねぇ。