[ale] md5sum weirdness on firefox -- SOLVED

[Joe Bayes]

Geoffrey typeth:
>Joe Bayes wrote:

>> Solution 2: No, there's nothing wrong with md5sum: it was my
>>   router. When my router does its own peculiar version of NAT, it
>>   replaces 216.86.915.37 with 192.168.0.2 in incoming packets. In
>>   outgoing packets, it reverses the process. Apparently it does this
>>   substitution in packet data as well as in the routing information,
>>   and firefox-1.5.0.9-3.fc6.i386.rpm just happened to contain (the
>>   encoded representation of) 216.86.195.37 somewhere in the data.
>
>This makes absolutely no sense to me.  If you downloaded the file, it 
>should not contain any remnants of your network configuration.

Exerpted from http://www.azureuswiki.com/index.php/NinetyNine :

   Some routers employ a trick called game mode, rewriting internal
   and external IP address bytes within incoming and outgoing
   packets. This allows older games that hard-code IP addresses to
   function behind a NAT setup. However, when such an address-byte
   sequence is coincidentally present within a file being sent via the
   BitTorrent protocol, the router mistakenly rewrites the data. This
   changes the content of the packet, which fails hash-checking. Any
   incoming packet that has a byte sequence that happens to match the
   address byte sequence is susceptible to mangling, an event
   estimated to happen once for about every 4GB of data transferred.

I don't *know* that this is what is going on, but it's currently my
best guess. 

Joe
--
Joe Bayes -- jbayes at spoo.mminternet.com