Verizon Users Can't See Site

[Hauke Lampe]

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On 14.09.2010 19:32, cyberseal at comcast.net wrote:

> Today I was given access to a Linux box on the Verizon network that is using their DNS server 71.252.0.12, which is affected by this problem.

Your nameserver software is case-sensitive where it should not be:

dig +norec www-mbclive.mbc.irides.com. @216.250.250.136
- -> correct answer

dig +norec www-mbclive.mbc.irides.COM. @216.250.250.136
- -> NODATA answer

If Verizon's DNS resolvers use 0x20[1] or modify the character case in
any way, they cannot find the right answer.

You should complain to your DNS LB vendor. Their implementation appears
to be too minimalistic.

dig +norec version.bind txt ch @216.250.250.136
;; Question section mismatch: got version.bind/TXT/IN
;; connection timed out; no servers could be reached



Hauke.


[1] Use of Bit 0x20 in DNS Labels to Improve Transaction Identity
    http://tools.ietf.org/html/draft-vixie-dnsext-dns0x20
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