Cisco 687 + Belkin Wireless network question

[Travis Pupkin]

Hi,

I have a home network with a Windows 2000 Pro Desktop and an XP Pro
laptop. It currently works, but with problems, and I think I know why.
I'm hoping someone here can please clarify some of my confusion.

I have a Cisco 678 DSL Modem/Router connected to the phone jack (with
filter, of course). This connects to my Belkin 802.11g Wireless
DSL/Cable Gateway Router, which connects via LAN to my desktop and WLAN
to my laptop. I have a dynamic IP and the Cisco is set for DHCP.

When I first set-up the network (pretty blindly, I must admit) I got it
to work and I could log in to the web interface of the Belkin to setup
security parameters, but my internet connection would get disconnected
for one minute exactly every 18 minutes. I realized -- I think, it was
more of a guess -- that I had set-up both the Cisco and the Belkin to
act as routers, and they were interfering with each other. So I turned
off the router function of the Belkin, using it only as a wireless
access point, and then my connection worked uninterrupted, but I lost
all access to the Belkin's web interface and my security settings
disappeared, leaving my wireless network exposed and I also now have NAT
problems (I'm still not exactly sure what that means, but people tell me
that I have NAT problems. Unfortunately, all the stuff I can find out
about fixing that with the Cisco are for static IPs. Mine is dynamic).

So here's what I'm thinking, but I'm not sure if it's possible or how to
do it: I should use the Cisco **only** as a DSL modem, and not as a
router, and let the Belkin act as my router **and** wireless access
point. Would this be an easier configuration for someone like me to set
up port forwarding and secure my network? I do find the Belkin's
interface much less vexing than hyperterminaling into the Cisco. But
that's partially because I'm a lazy idiot who only half-understands what
I've just typed.

Any help would be appreciated.

Thanks.

 

[Ross Durie]

So when you lost the connection for 1 minute every 18 minutes which router
was timing out, i.e., which router's ADSL or WAN led would go out?

 

[Travis Pupkin]

So when you lost the connection for 1 minute every 18 minutes which router
was timing out, i.e., which router's ADSL or WAN led would go out?

I have no idea. When I disabled the router in the Belkin, there were no
more interruptions, but I figured it was a conflict between the two
devices trying to do each other's job, rather than a problem with just
one of them.

 

[James Egan]

Unfortunately, all the stuff I can find out
about fixing that with the Cisco are for static IPs. Mine is dynamic

It's a dynamic address on the external interface ie. the *public*
address assigned by your isp. Not to be confused with the *private*
address of the LAN interface.

Both of the routers will more than likely have dhcp servers on by
default so you need to switch it off on one of them, preferably the
Belkin. Then give both the routers static addresses on their LAN
interfaces which are outside the range of the dhcp pool of your
remaining dhcp server but still on the same network.

Then you will know precisely the address of the access point to set up
the wireless settings and also the address of the default gateway.


Jim.

 

[Travis Pupkin]

It's a dynamic address on the external interface ie. the *public*
address assigned by your isp. Not to be confused with the *private*
address of the LAN interface.

Both of the routers will more than likely have dhcp servers on by
default so you need to switch it off on one of them, preferably the
Belkin. Then give both the routers static addresses on their LAN
interfaces which are outside the range of the dhcp pool of your
remaining dhcp server but still on the same network.

Then you will know precisely the address of the access point to set up
the wireless settings and also the address of the default gateway.


Jim.

Thanks for the info, Jim. I've reset both routers to their default
settings and am working through configuring them properly, but every
time I think I'm close to doing it correctly, I knock one of the two
PCs, or the whole network, off line, and have to reset everything and
start over again.

Currently I have the Cisco running DHCP and it's assigning 10.0.0.2 to
the Belkin. The Belkin has DHCP disabled, but I can't find where to
assign the private static IPs. Do I do this only on the individual
machines' TCP/IP properties? Or am I also supposed to manually set up
their IPs in one of the routers?

And I need to set NAT on both routers, right? NAT from the Cisco to the
Belkin and the Belkin to the machine IP/port that I need forwarded? I
think I understand that part now, but I'm not getting the syntax correct
or the ports right in the Cisco because it's not doing what it's
supposed to (I don't think).

Sorry for being such an idiot about this stuff. Thanks for any and all
help.

 

[James Egan]

Currently I have the Cisco running DHCP and it's assigning 10.0.0.2 to
the Belkin. The Belkin has DHCP disabled, but I can't find where to
assign the private static IPs.

Presumably the Cisco is at 10.0.0.1 then?

It's not absolutely essential that the Belkin has a static address but
it would be helpful if it was so that you always know how to connect
to it without having to find out its address.

Leave it with its assigned address for now. You can return to this
later once the rest is working.

Do I do this only on the individual
machines' TCP/IP properties? Or am I also supposed to manually set up
their IPs in one of the routers?

Set each pc to receive an ip address automatically and the cisco will
assign them individual addresses out of its pool in the same way that
it gave the Belkin its address of 10.0.0.2

You don't have to configure the cisco router other than to ensure dhcp
is switched on.

And I need to set NAT on both routers, right?

No. The Cisco will be performing NAT for the whole network. The Belkin
is now just a switch or access point. You don't need to configure it
to stop using NAT, you just need to leave the external (WAN) interface
unplugged. You shouldn't have any cables plugged in there. The cisco
router and the wired pc should both be plugged into the LAN ports of
the Belkin.

NAT from the Cisco to the
Belkin and the Belkin to the machine IP/port that I need forwarded? I
think I understand that part now, but I'm not getting the syntax correct
or the ports right in the Cisco because it's not doing what it's
supposed to (I don't think).

Sorry for being such an idiot about this stuff. Thanks for any and all
help.

You don't need any port forwarding. That's not required for what you
are trying to do.

Jim.
..

 

[James Egan]

I've looked up the manuals of those routers to try and find an easy
solution for you.

The Belkin (as you pointed out) is far more user friendly. The cisco
online manual I looked through wasn't clear enough about dhcp to give
you any advice.

The upshot of it all is that the Belkin router has a default ip
address of 192.168.2.1 and dhcp pool of 2 to 100. So you can easily
set up your network as follows :-

Switch dhcp off on the cisco and give it a static ip address of
192.168.2 254

set interface eth0 address 192.168.2.254
set interface eth0 mask 255.255.255.0

That will put the cisco in the same network (192.168.2. 1 to 254) as
the belkin without clashing with the dhcp pool which is from 2 to 100

Reset the defaults on the belkin then connect the wired pc and cisco
router to the LAN ports (of the belkin).

The pc 's will then get their ip addresses from the Belkin within the
range 192.168.2.2 to 100 and need the default gateway set to the ip
address of the cisco at 192.168.2.254


Jim.

 

[Travis Pupkin]

I've looked up the manuals of those routers to try and find an easy
solution for you.

The Belkin (as you pointed out) is far more user friendly. The cisco
online manual I looked through wasn't clear enough about dhcp to give
you any advice.

The upshot of it all is that the Belkin router has a default ip
address of 192.168.2.1 and dhcp pool of 2 to 100. So you can easily
set up your network as follows :-

Switch dhcp off on the cisco and give it a static ip address of
192.168.2 254

set interface eth0 address 192.168.2.254
set interface eth0 mask 255.255.255.0

That will put the cisco in the same network (192.168.2. 1 to 254) as
the belkin without clashing with the dhcp pool which is from 2 to 100

Reset the defaults on the belkin then connect the wired pc and cisco
router to the LAN ports (of the belkin).

The pc 's will then get their ip addresses from the Belkin within the
range 192.168.2.2 to 100 and need the default gateway set to the ip
address of the cisco at 192.168.2.254


Jim.

Thanks for all your help. It seems to be working now. I think I did what
you told me to, but I'm not sure in practice.

 

[James Egan]

Thanks for all your help. It seems to be working now. I think I did what
you told me to, but I'm not sure in practice.

Good to hear.

One other thing I forgot to mention iif you use the belkin for dhcp
instead of the cisco is the nameservers.

When your cisco router make its ppp connection to your ISP it will
receive its (public) ip address and also details of the ISP's
nameservers. If your pc's get their ip addresses allocated by the
cisco (running dhcp) then this nameserver information is passed along
also. If the belkin is used to allocate ip addresses on the LAN, it
won't know the nameserver details to pass on to the pc's so you will
have to configure that manually on the dns tabs of the pc's. You can
either enter the LAN address of the cisco router the same as the one
for default gateway or you can enter the public ip address(es) of your
isp's nameservers or both.


Jim.