Aliases and 403 error

Question

I use a Xserve with MacOS 10.4.3 in order to host our clients' web sites and databases. We have been hosting more than 10 sites for a year now, but I encountered a bug with our latest client that I do not understand (I replaced our client's name by "client" in the following):
Main site:
URL: www.client.com
Root: /Volumes/MediaHD/FTP/client/web
Database site:
URL: base.client.com
Root: /Library/WebServer/Opsis/client
Both sites work fine, but my client wanted to access the database through the following URL: www.client.com/base. So, in SA, I created an URL alias for www.client.com:
/base -> /Library/WebServer/Opsis/client
And here comes the bug:
When I save the configuration in SA, everything works fine for few seconds, i.e. the URL "www.client.com/base" goes to "/Library/WebServer/Opsis/client/index.php" which is the home page for "base.client.com". However, if I wait few seconds or reload the page 2 or 3 times, I get a 403 error message. Sometimes, it is even weirder: every time I reload the page I get a new question mark, because the access to an image has become forbidden, until I finally get the 403 error message.
Looking at the logs, I get nothing, except "81.66.29.66 - - [23/Jun/2006:19:11:23 +0200] "GET /base HTTP/1.1" 403 297" in access.log.
Of course, "base.client.com" still works, with no 403 error, whereas it goes exactly to the same home page, i.e. "/Library/WebServer/Opsis/client/index.php".
Another oddity: there is another URL alias for www.client.com, which is:
/media -> /Volumes/MediaHD/media/client
and this one works fine!
I deactivated WebDAV for both sites, and deleted the Realms I had defined too. But nothing changed.
You will find below my httpd.conf file for this site (0014any_80www.client.com.conf):
## Default Virtual Host Configuration
<VirtualHost *:80>
ServerName www.client.com
ServerAdmin [email protected]
DocumentRoot "/Volumes/MediaHD/FTP/client/web"
DirectoryIndex index.html index.php
CustomLog '|/usr/sbin/rotatelogs "/var/log/httpd/www.client.com/access_log" 86400' "%h %l %u %t \"%r\" %>s %b"
ErrorLog '|/usr/sbin/rotatelogs "/var/log/httpd/www.client.com/error_log" 86400'
ErrorDocument 404 /error.html
<IfModule mod_ssl.c>
SSLEngine Off
SSLLog "/var/log/httpd/sslenginelog"
SSLCertificateFile "/etc/certificates/Default.crt"
SSLCertificateKeyFile "/etc/certificates/Default.key"
SSLCipherSuite "ALL:!ADH:RC4RSA:+HIGH:+MEDIUM:+LOW:!SSLv2:+EXP:eNULL"
</IfModule>
<IfModule mod_dav.c>
DAVLockDB "/var/run/davlocks/.davlock100"
DAVMinTimeout 600
</IfModule>
<Directory "/Volumes/MediaHD/FTP/client/web">
Options All -Indexes -ExecCGI -Includes +MultiViews
<IfModule mod_dav.c>
DAV Off
</IfModule>
AllowOverride None
</Directory>
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_METHOD} ^TRACE
RewriteRule .* - [F]
</IfModule>
<IfModule mod_alias.c>
Alias "/media" "/volumes/mediahd/media/client"
Alias "/base" "/library/webserver/opsis/client"
</IfModule>
LogLevel debug
ServerAlias www2. client.com
</VirtualHost>
Any suggestion would be welcome, since I really do not understand what is going on.
Thanks
David

Answer 1

What does the error log say?
It is usually more relevant in debugging 403 errors than the access log.
The only odd thing I see is that you're aliasing /base to /Library/WebServer/Opsis/client whereas I'd expect it to be /Library/WebServer/Documents/Opsis/client (note the additional /Documents directory.
This may or may not be the problem depending on where the base.client.com site is configured.