🚀 go-pugleaf

Is it necessary to filter all URLs or is it acceptable if someone bypasses
the filter ( i.e. by removing / changing the proxy setting from their
browser ) ?

If the last is not ok you will have to setup a proxy system like some ISPs
do :

Put your proxy on a dedicated machine inbetween the network and the
connection to the internet : internal router <-> your proxy <-> internet.
the internal router should be configured to route all outgoing network
traffic to your proxy...
there you have the ability to filter everything you want even without any
proxy setting in the user's browser...

IIRC Indy comes with an example for a simple proxy server... perhaps this is
a good starting point...


If you can't do such a setup and need to run on the user's computer locally
then you will have to write some sort of low-level filter ( below WinSock )
which really need a lot of time ( I don't know of any good library for
this ) and is pretty hard to get working under a broad range of network
setups... and the users could easily remove it ( depending on which OS is
running )...

If you need to filter any URL and not only HTTP then you will end up writing
some sort "mini-firewall" which in turn will take a lot of time - IIRC there
was a thread in .internet.winsock or so where somebody wanted to learn
writing a firewall and got some links with firewall source code as a
starting point.

Yahia