Locking Firefox Proxy Setting

[gilman22]

I am trying to find a way to prevent a user from changing the firefox proxy setting and bypass my Internet filter. Any help would be appreciated

[SpaceTeddy]

even if you lock it, users that want to go around it will find another way (i.e. use a different browser)... The only way (i can think of at the moment) to make sure that you proxy is not bypassed it to make it transparent and channel the users through it no matter what they have set in their profiles.
This is just an idea for an alternate solution since i think forcing settings on the client side usually work as long as the user is not clever enough - but as soon as you have a person that knows a little more than the average joe doe most client side security settings can be bypassed.
So my suggesting would be to setup a transparent proxy - there is not setting on the client - and there is no way of bypassing it (well - there is, but people who can do that you can't control anyway... besides bypassing a transparent proxy is way beyond the average or even the advanced user).

I know that this does not really answer your question... If this is of no interest to you - ignore me