[COLUG] Apache Rewrite Rules

[Joshua Kramer]

Howdy All,

Does anyone have experience debugging Apache Rewrite rules?  I have a 
blogging website hosted off my DSL line, and I therefore have two 
installations.  When I hit my blog from the inside:

http://192.168.2.151/~josh/elgg_prod/jb01/weblog

It works great!  But from the outside,

http://www.globalherald.net/jb01/weblog

I get a 404 and the Error Log notes that it can't find the file.  I'm 
using the same Rewrite rules in both installations.  So, Apache should be 
using, when I hit http://www.globalherald.net/jb01/weblog, this rule:

RewriteRule ^([A-Za-z0-9]+)\/weblog\/?$ _weblog/index.php?weblog_name=$1

Then, apache should obey this rule and redirect to:

http://www.globalherald.net/_weblog/index.php?weblog_name=jb01

Incidentally, if you hit that last URL it works fine.  Apache does indeed 
obey that rule on the internal site (192.168.2.151) but not on the 
external one.

Any idears about how I could debug this behavior?  (Using the Apache in
httpd-2.0.52-12.ent.centos4)

Thanks,
-Josh