Re: Connecting Cisco 831 Router behind the D-Link Router


"Trendkill" <jpmason@xxxxxxxxx> wrote in message
news:1174842273.743040.73750@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Mar 25, 9:00 am, "Yajesh Shanker" <y...@xxxxxxxxxx> wrote:
Hi!
My home network uses D-Link Router providing 192.168.1.x addrress
throughout
our home network. When I connect Cisco 831 Router so that I can be be
part
of our office VPN network, My D-Link address scheme changes to 10.10.x.x.
I'm not sure why it is doing that.

My Cisco 831 router is sitting behind D-Link router. The following may
illustarte the setup:

Cable Modem----DHCP------->WAN Port on D-Link--------->One of the LAN
Ports-------192.168.1.x----->Cisco Router

The Cisco Router does see the 192.168.1.x adress provided by D-Link.

However, when I disconnect Cisco Router LAN Cable from the D-Link router,
I
am back to 192.168.1.x address throught my home network and obviously
everything works fine.

Can one explain the possible cause of this and what should I set/check to
solve this issue.
yaj

Sounds to me like your Cisco router is setup for dhcp and is giving
out IP addresses to your dlink clients before your dlink can respond.
At its most basic level, the dlink is a switch, and just had a dhcp
server built into its software. When a client sends a dhcp request,
the dlink will forward that request out all LAN ports as it is a
simple broadcast. Since there are usually no other dhcp servers, the
dlink's dhcp server request is used and gives out a 192.168.x.x. But,
and this is not uncommon, the Cisco router is probably receiving the
request and is configured to give out a 10.x. network range address
via its own dhcp configuration. You need to look at your cisco
config......why not just use the cisco router as both your gateway and
vpn termination? I'm sure your office is using private IP addressing
anyway, so its not like client traffic will mistakenly go there...and
if your office is allowing vpns in this scenario, obviously they
aren't that security conscious.

Just a guess........


Interestingly you touch the exact points that I thought seemed to be
happening.

Understood! Cisco and D-Link having inherent router specific functionality,
will
generate an IP Address in the range specfied. i.e. 192,168.1.x and
10.10.10.x
respectively.

What I think is happening, Ciscco is passing that IP to D-Link and
sometimes D-Link
turns around and overrides its own generated IP (192.168.1.x) and passes
along 10.10.10.x
address within Home Network. Seems like a voodoNetwork setup.

Having learnt this, it also means if Cisco Router traffic is channeled
through D-Link Gateway
address 192,168.1.1. Is this a correct statement?

Tell me!
Does htis mean, that home network is exposed to Cisco router while on VPN
through Cisco
connection?

I think to solve this entire issue it would be ebst to subscribe to 2
seperate IP addresses and
segment two networks using NetGear Hub. Network A will service 192.68.1.x
while Network B
will service 10.10.10.x devices.


Yajesh


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