htaccess，用户代理字符串和Firefox

Question

new here.
so please forgive if i don't post correctly.

I am trying to use this code in my htaccess file,

RewriteCond %{HTTP_USER_AGENT} ^DISCo Pump [NC,OR]

the code works fine in chrome or IE, (i have many others using the same formula)
but it is only firefox that throws me an error 500 page.
and cpanel error log says
[alert] [client xx.xx.xx.xxx] /home/user/public_html/.htaccess: RewriteCond: bad flag delimiters
this has me stumped because it works fine in IE and chrome browsers.
It is only when i view my website with firefox that it generates the error.
can anyone explain this please ?
does firefox possibly use"disco pump" as part of its browser coding?
I am a novice not a Guru.
thanks.

Answer 1

RewriteCond %{HTTP_USER_AGENT} ^DISCo Pump [NC,OR] are 5 'parts' instead of 4 if you split it on spaces. I think the rule doesn't match or fails on one of the previous conditions in other browsers. If mod_rewrite reaches this condition, it sees Pump as the 3rd argument and expects flags there, because the space is not escaped. The fix is simply to escape the space with a \\ .

RewriteCond %{HTTP_USER_AGENT} ^DISCo\ Pump [NC,OR]