apache mod_write RewriteCond %{HTTP_USER_AGENT} Doesn't works

Question

I am trying to redirecto to other machine by filtering the user agent in a apache web server. I have a web server in the machine with the ip 192.168.2.11, but this web server only should send the page to the requests WITHOUT this user agent:

Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:99.0) Gecko/20

Instead it should redirect the request to 192.168.1.40 that have other web server running.

I tried to modify the file /etc/apache2/apache2.conf with the next code

RewriteEngine on
RewriteCond ${HTTP_USER_AGENT} "!=Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:99.0) Gecko/20"
RewriteRule ^(.*)$ https://192.168.1.40 [L,R=302]

But doesn't work, it always show index.html from the 192.168.2.11 machine (it doesnt redirect). Why? How can I do that?

EDIT

I think I'm indicating wrong the user_agent because this works fine:

RewriteEngine on
RewriteCond ${HTTP_USER_AGENT} Ubuntu
RewriteRule ^(.*)$ - [R=403,L]

So the question is, how can I specify a particular user_agent? and how can I spacify all user_agent exept that particular user_agent?

Answer 1

As per the documentation of the RewriteCond, you can use either regular expressions or plain string

... CondPattern is usually a perl compatible regular expression, but there is additional syntax available to perform other useful tests against the Teststring: ...

So, in order to rewrite for any user agent except this one "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:99.0) Gecko/20", you have to use the following:

RewriteEngine on
RewriteCond %{HTTP_USER_AGENT} "!=Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:99.0) Gecko/20"
RewriteRule ^/(.*)$ https://192.168.1.40/$1 [L,R=302]

You can also combine multiple RewriteCond for the same RewriteRule. But this is not what you are looking for.