Re: Problems sending mail from .mumble

[Duane Wessels <wessels () packet-pushers com>]

> Is there an application that treats a local file specifier and a host 
> specifier indistinguishably? If so, how does it deal with strings (like those 
> I listed above) that could potentially be executables as well as domain 
> names?

Looking at the 2007 DITL data (traces from DNS roots) its interesting
to see traffic for invalid TLDs that look just like filename
extensions.  For example:

% of all   TLD/
Queries    extension
---------- -----------
0.182       txt
0.055       htm
0.051       c
0.049       lib
0.041       jpg
0.026       gif
0.012       html
0.011       php
0.005       exe

(Note, those really are percentages.)

I have no idea what applications are behind them, but it indicates
that there is software out there that has a hard time telling the
difference between a filename and a hostname.  Or maybe its (ab)using
the DNS to help make the decision.

FWIW I was able to find one application, the text browser 'links,'
which accepts either filename or hostnames as its commandline
argument.  From what I can tell its algorithm is something like
this:

   - if tld/extension has two letters --> URL
   - if less than two letters --> File
   - if tld/extension is in list of known gTLDs --> URL
   - else --> File

DW