P
Phil D
Hi all,
I have set up VPN on my local network and thought I had it all working
properly. However I have run into a slight problem in setting up the packet
filters on the external NIC.
The layout is thus :-
router ( 192.168.0.1)
|
|
switch ----------------------PC-----PC-----PC-----etcetc
|
|
VPN server (192.168.0.99 set in DMZ for router)
[also IIS] (192.168.0.100)
NIC 1 (x.x.x.99) is set in the router DMZ and was intended as the external
VPN card
NIC 2 (x.x.x.100) is used for web and ftp access, with port redirection set
on the router for ports 21 & 80.
As I said, I got everything up and running ok, clients could vpn in, browse
network, access web, collect email etc. I then tried to add the input
filters onto NIC 1 so that only vpn access was possible on that ip address.
The filters I added were the following input filters
Source add source mask dest add dest mask prot
source port dest port
any any x.x.x.99 255.255.255.255
47 any any
any any x.x.x.99 255.255.255.255
TCP any 1723
When I did this the clients could still vpn in, but could no longer browse
the network or access shares on the network machines. After a bit of
head-scratching, I realised that the problem is that the vpn box is not
routing between the two network cards (as they're both on the same subnet).
Now I suppose one solution is to go and buy another router and modify the
network topology to this
router (10.0.0.1)-------------------
| |
| (10.0.0.3)
| (10.0.0.2) VPN box
router -------------------------- (192.168.0.100)
| (192.168.0.1)
|
switch------------PC----PC---etcetc
which I assume would work cause the vpn box would then route traffic from
one nic to the other.
However, rather than spend money, I decided to try adding extra filters to
eliminate the problem. The reason for this is that the vpn network card is
not routing to the second network card, so it must be servicing requests on
behalf of vpn clients itself. That been the case, the basic input filters
would interfere with the responses from the local network machines.
To solve this I added the following input filters:-
Source add source mask dest add dest mask prot
source port dest port
192.168.0.0 /24 x.x.x.99 /32
TCP Any Any
192.168.0.0 /24 x.x.x.99 /32
UDP Any Any
192.168.0.0 /24 x.x.x.99 /32
ICMP Any Any
192.168.0.0 /24 x.x.x.99 /32
Any Any Any
Doing this again enabled the vpn clients to browse the local network again,
and see the machines on the network, however they were still unable to
access resources on those machines or even see the resources on those
machines. ( I should add that I am running WINS on the vpn server, bound to
the 192.168.0.100 nic) I should also mention that the vpn clients obtain ip
addresses from a pool on the same subnet.
What I'd like to know is if there are more rules I can add to get my vpn
clients able to access resources on network machines again, and if so what
those rules are.
However, I may be completely wrong in my reasoning about this problem, and
the issue lies elsewhere. If so maybe someone could please let me know.
Many thanks in advance
Phil
I have set up VPN on my local network and thought I had it all working
properly. However I have run into a slight problem in setting up the packet
filters on the external NIC.
The layout is thus :-
router ( 192.168.0.1)
|
|
switch ----------------------PC-----PC-----PC-----etcetc
|
|
VPN server (192.168.0.99 set in DMZ for router)
[also IIS] (192.168.0.100)
NIC 1 (x.x.x.99) is set in the router DMZ and was intended as the external
VPN card
NIC 2 (x.x.x.100) is used for web and ftp access, with port redirection set
on the router for ports 21 & 80.
As I said, I got everything up and running ok, clients could vpn in, browse
network, access web, collect email etc. I then tried to add the input
filters onto NIC 1 so that only vpn access was possible on that ip address.
The filters I added were the following input filters
Source add source mask dest add dest mask prot
source port dest port
any any x.x.x.99 255.255.255.255
47 any any
any any x.x.x.99 255.255.255.255
TCP any 1723
When I did this the clients could still vpn in, but could no longer browse
the network or access shares on the network machines. After a bit of
head-scratching, I realised that the problem is that the vpn box is not
routing between the two network cards (as they're both on the same subnet).
Now I suppose one solution is to go and buy another router and modify the
network topology to this
router (10.0.0.1)-------------------
| |
| (10.0.0.3)
| (10.0.0.2) VPN box
router -------------------------- (192.168.0.100)
| (192.168.0.1)
|
switch------------PC----PC---etcetc
which I assume would work cause the vpn box would then route traffic from
one nic to the other.
However, rather than spend money, I decided to try adding extra filters to
eliminate the problem. The reason for this is that the vpn network card is
not routing to the second network card, so it must be servicing requests on
behalf of vpn clients itself. That been the case, the basic input filters
would interfere with the responses from the local network machines.
To solve this I added the following input filters:-
Source add source mask dest add dest mask prot
source port dest port
192.168.0.0 /24 x.x.x.99 /32
TCP Any Any
192.168.0.0 /24 x.x.x.99 /32
UDP Any Any
192.168.0.0 /24 x.x.x.99 /32
ICMP Any Any
192.168.0.0 /24 x.x.x.99 /32
Any Any Any
Doing this again enabled the vpn clients to browse the local network again,
and see the machines on the network, however they were still unable to
access resources on those machines or even see the resources on those
machines. ( I should add that I am running WINS on the vpn server, bound to
the 192.168.0.100 nic) I should also mention that the vpn clients obtain ip
addresses from a pool on the same subnet.
What I'd like to know is if there are more rules I can add to get my vpn
clients able to access resources on network machines again, and if so what
those rules are.
However, I may be completely wrong in my reasoning about this problem, and
the issue lies elsewhere. If so maybe someone could please let me know.
Many thanks in advance
Phil