13 root nameservers

2007/03/09

So it turns out there can only be 13 root nameservers because of a DNS UDP packet size issue.

Got that from: http://icann.org/announcements/announcement-08mar07.htm which makes a few interesting comments about DNS.

It makes sense when you think about it. Here’s the 462 byte packet capture from “host -t ns .” Which for some reason I get different responses from from my upstream resolver. This one looks okay though.

0000   00 19 e3 0a 0f 7f 00 09 5b 4e 0a 92 08 00 45 00  ........[N....E.
0010   01 d0 85 c5 00 00 3d 11 cd 11 53 92 15 05 c0 a8  ......=...S.....
0020   00 07 00 35 c9 31 01 bc ce 32 6a cc 81 80 00 01  ...5.1...2j.....
0030   00 0d 00 00 00 0d 00 00 02 00 01 00 00 02 00 01  ................
0040   00 01 cc fe 00 14 01 66 0c 72 6f 6f 74 2d 73 65  .......f.root-se
0050   72 76 65 72 73 03 6e 65 74 00 00 00 02 00 01 00  rvers.net.......
0060   01 cc fe 00 04 01 67 c0 1e 00 00 02 00 01 00 01  ......g.........
0070   cc fe 00 04 01 68 c0 1e 00 00 02 00 01 00 01 cc  .....h..........
0080   fe 00 04 01 69 c0 1e 00 00 02 00 01 00 01 cc fe  ....i...........
0090   00 04 01 6a c0 1e 00 00 02 00 01 00 01 cc fe 00  ...j............
00a0   04 01 6b c0 1e 00 00 02 00 01 00 01 cc fe 00 04  ..k.............
00b0   01 6c c0 1e 00 00 02 00 01 00 01 cc fe 00 04 01  .l..............
00c0   6d c0 1e 00 00 02 00 01 00 01 cc fe 00 04 01 61  m..............a
00d0   c0 1e 00 00 02 00 01 00 01 cc fe 00 04 01 62 c0  ..............b.
00e0   1e 00 00 02 00 01 00 01 cc fe 00 04 01 63 c0 1e  .............c..
00f0   00 00 02 00 01 00 01 cc fe 00 04 01 64 c0 1e 00  ............d...
0100   00 02 00 01 00 01 cc fe 00 04 01 65 c0 1e c0 a4  ...........e....
0110   00 01 00 01 00 09 2f 0e 00 04 c6 29 00 04 c0 b3  ....../....)....
0120   00 01 00 01 00 08 ee 1c 00 04 c0 e4 4f c9 c0 c2  ............O...
0130   00 01 00 01 00 09 38 ff 00 04 c0 21 04 0c c0 d1  ......8....!....
0140   00 01 00 01 00 09 33 ef 00 04 80 08 0a 5a c0 e0  ......3......Z..
0150   00 01 00 01 00 09 29 a6 00 04 c0 cb e6 0a c0 1c  ......).........
0160   00 01 00 01 00 09 2f 0e 00 04 c0 05 05 f1 c0 3b  ....../........;
0170   00 01 00 01 00 09 2f 13 00 04 c0 70 24 04 c0 4a  ....../....p$..J
0180   00 01 00 01 00 09 1c 9f 00 04 80 3f 02 35 c0 59  ...........?.5.Y
0190   00 01 00 01 00 09 38 ff 00 04 c0 24 94 11 c0 68  ......8....$...h
01a0   00 01 00 01 00 09 23 b5 00 04 c0 3a 80 1e c0 77  ......#....:...w
01b0   00 01 00 01 00 09 38 ff 00 04 c1 00 0e 81 c0 86  ......8.........
01c0   00 01 00 01 00 09 38 ff 00 04 c6 20 40 0c c0 95  ......8.... @...
01d0   00 01 00 01 00 09 38 ff 00 04 ca 0c 1b 21        ......8......!

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