Blocking internet sharing

[Manish Pithwa]

hi,
I am searching for a s/w to block internet sharing on some computer
dynamically.
I have a LAN of 40 PCs with one leased line internet connection. one of
the 40 PCs has direct internet connection and connected to LAN switch
also. Other PCs on LAN access internet via this computer. All PC has
windows XP SP2. For Internet I created one connection and another for
LAN on main computer. Other remaining computers have only one
connection that is for LAN. All PCs are accessing internet by giving IP
address of gateway and DNS servers.

Can anybody suggest me any s/w to block internet on any PC
dynamically by just disabling internet sharing for that particular
computer from main PC where Internet connection is directly connected?
I want to control internet sharing by centralized system without
blocking file and data sharing on LAN. I want to keep file and printer
sharing on while blocking internet sharing simaltanously on any PC. For
both purpose only one communcation cable should be used from the PC to
the switch that interconnects all the systems of LAN.S/w should block
only internet sharing while unblocking file sharing. I think it would
be possible to block internet sharing and unblocking file sharing from
main PC simaltanously from where internet is accessed by other PCs.If
you have any solution to this problem plese tell me.


Manish Pithwa

 

[Guest]

If youhave a leased line then it would be more sensible to use a NAT router.
The only reson not to would be if the one direct PC has to have an IP address
that's visible from outside. Even then, this can usually be got around by
making that computer the DMZ.

The more sophisticated routers allow for selective Internet access.

The basic alternative would be to use fixed IP addresses, and remove the
default gateway from those not getting Internet access.

A third possibility is to use a proxy such as Jana Server.

 

[Manish Pithwa]

Thanks for help,
But I am unable to use router or any other h/w device. I can't afford
more h/w. I want to solve problem using exsiting S/w and H/w. I can
switch to new OS which can run on desktop machine easily.

 

[Manish Pithwa]

how can we control users from one PC by XP n/w logon dynamically? I
always sit and use main computer from where other computers access
internet, I want that If I disable internet for specific computer, it
should be disabled until I enable access for that computer by sitting
on main computer. XP logon will require to let users passwords and
need to change passward at regular interval when they need to block, or
to enter password by me on all 40 PC when users wants to use internet.
Otherwise all users will be free to use internet. I want any s/w
solution.