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ADSL modem and WIFI Router

Last response: in Wireless Networking
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July 18, 2004 9:19:37 PM

Archived from groups: alt.internet.wireless (More info?)

I'd like to connect my ADSL modem/router to my WIFI router, with the
WIFI router handling the DCHP. The WIFI router has a port for a
direct LAN connection with the modem. I've tried everything I can
think of, but I'm out of ideas at this point, can anyone help?

The modem is a ZyXEL Prestige 623R-T1
(ftp://ftp.zyxel.com/P623R-T1/document/P623R-T1_v3-40_Us...)

and the WIFI router is a 3COM 3CRWE554G72
(http://support.3com.com/infodeli/tools/hubs/off-con/pdf...)

Many thanks

More about : adsl modem wifi router

Anonymous
July 18, 2004 10:12:15 PM

Archived from groups: alt.internet.wireless (More info?)

On 18 Jul 2004 17:19:37 -0700, forumemail@eircom.net (FE) wrote:

>I'd like to connect my ADSL modem/router to my WIFI router, with the
>WIFI router handling the DCHP. The WIFI router has a port for a
>direct LAN connection with the modem. I've tried everything I can
>think of, but I'm out of ideas at this point, can anyone help?
>
>The modem is a ZyXEL Prestige 623R-T1
>(ftp://ftp.zyxel.com/P623R-T1/document/P623R-T1_v3-40_Us...)
>
>and the WIFI router is a 3COM 3CRWE554G72
>(http://support.3com.com/infodeli/tools/hubs/off-con/pdf...)

Well, it's a classic problem of two routers. I can see three ways to
make it work.

1. This is called double NAT. Setup the Zyxel as a router with LAN
port address at 192.168.1.1 (the default). Setup the 3Scum wireless
router with a static IP:
IP Address 192.168.1.2
Gateway 192.168.1.1
Netmask 255.255.255.0
DNS1 (real DNS server IP address)
DNS2 (the other real DNS serveri IP address)
On the LAN port of the 3Scum router, setup:
IP Address 192.168.5.1
Netmask 255.255.255.0
Have it dispense DHCP addresses starting at 192.168.5.100.
The "5" can be any number to 254 except "1" which is already being
used.

Some routers complain if you re-use any Class B address, so an
alternative would be:
IP Address 10.0.0.1
Netmask 255.255.255.0
DHCP start 10.0.0.100

The problem with this arrangment is that services that must come from
the internet to the workstations need to drill through two routers.
Configuration is easy enough but no fun.

2. Setup the Zyxel for a DMZ that points to the 3Scum WiFi router.
This is exactly the same as #1 except that you don't have have to deal
with all the services on the Zyxel, only on the 3Scum.

3. Setup the 3Scum router as if it were an access point (wireles
bridge) and completely ignore the router (WAN) port. This is what I
would prefer. Just plug a cable from a LAN port on the Zyxel to a LAN
port on the 3Scum. You *MAY* need to use a reversing CAT5 cable.
Make sure the lights show a connection. See:
http://kbserver.netgear.com/kb_web_files/n101236.asp
for the basic setup and some clues on the settings. Just remember
that the WAN port on the 3Scum goes nowhere.

>Many thanks

One thank is usually sufficient.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
Anonymous
July 18, 2004 11:53:02 PM

Archived from groups: alt.internet.wireless (More info?)

So what is it that is not working? Does it not assign the IP address? IF
so, when you manually assign an IP (and DNS servers) does it work?

--
Bob Alston

"FE" <forumemail@eircom.net> wrote in message
news:6b605e7.0407181619.791c72b0@posting.google.com...
> I'd like to connect my ADSL modem/router to my WIFI router, with the
> WIFI router handling the DCHP. The WIFI router has a port for a
> direct LAN connection with the modem. I've tried everything I can
> think of, but I'm out of ideas at this point, can anyone help?
>
> The modem is a ZyXEL Prestige 623R-T1
> (ftp://ftp.zyxel.com/P623R-T1/document/P623R-T1_v3-40_Us...)
>
> and the WIFI router is a 3COM 3CRWE554G72
>
(http://support.3com.com/infodeli/tools/hubs/off-con/pdf...
..pdf)
>
> Many thanks


---
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Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.721 / Virus Database: 477 - Release Date: 7/16/2004
Related resources
July 19, 2004 4:48:20 PM

Archived from groups: alt.internet.wireless (More info?)

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<747mf0tict8k4sg6ggv3nd2bqhjatr20ns@4ax.com>...
> On 18 Jul 2004 17:19:37 -0700, forumemail@eircom.net (FE) wrote:
>
> >I'd like to connect my ADSL modem/router to my WIFI router, with the
> >WIFI router handling the DCHP. The WIFI router has a port for a
> >direct LAN connection with the modem. I've tried everything I can
> >think of, but I'm out of ideas at this point, can anyone help?
> >
> >The modem is a ZyXEL Prestige 623R-T1
> >(ftp://ftp.zyxel.com/P623R-T1/document/P623R-T1_v3-40_Us...)
> >
> >and the WIFI router is a 3COM 3CRWE554G72
> >(http://support.3com.com/infodeli/tools/hubs/off-con/pdf...)
>
> Well, it's a classic problem of two routers. I can see three ways to
> make it work.
>
> 1. This is called double NAT. Setup the Zyxel as a router with LAN
> port address at 192.168.1.1 (the default). Setup the 3Scum wireless
> router with a static IP:
> IP Address 192.168.1.2
> Gateway 192.168.1.1
> Netmask 255.255.255.0
> DNS1 (real DNS server IP address)
> DNS2 (the other real DNS serveri IP address)
> On the LAN port of the 3Scum router, setup:
> IP Address 192.168.5.1
> Netmask 255.255.255.0
> Have it dispense DHCP addresses starting at 192.168.5.100.
> The "5" can be any number to 254 except "1" which is already being
> used.
>
> Some routers complain if you re-use any Class B address, so an
> alternative would be:
> IP Address 10.0.0.1
> Netmask 255.255.255.0
> DHCP start 10.0.0.100
>
> The problem with this arrangment is that services that must come from
> the internet to the workstations need to drill through two routers.
> Configuration is easy enough but no fun.
>
> 2. Setup the Zyxel for a DMZ that points to the 3Scum WiFi router.
> This is exactly the same as #1 except that you don't have have to deal
> with all the services on the Zyxel, only on the 3Scum.
>
> 3. Setup the 3Scum router as if it were an access point (wireles
> bridge) and completely ignore the router (WAN) port. This is what I
> would prefer. Just plug a cable from a LAN port on the Zyxel to a LAN
> port on the 3Scum. You *MAY* need to use a reversing CAT5 cable.
> Make sure the lights show a connection. See:
> http://kbserver.netgear.com/kb_web_files/n101236.asp
> for the basic setup and some clues on the settings. Just remember
> that the WAN port on the 3Scum goes nowhere.
>
> >Many thanks
>
> One thank is usually sufficient.

LOL, well I figured it was a big enough of a problem to need a few
thanks!

Appreciate all the advice ..what I've ended up doing (and after many
hours spent fiddling about)is configuring the modem to act as a bridge
(the setting for this was in the wizard ..things I usually stay well
away from, and why I didn't spot it sooner) this deactivates the DCHP,
allowing the WiFi router handle everything.

I've left the default IP for the router at 192.168.1.1 (when I changed
it, it wouldn't work!) with the WiFi on 192.168.1.2, everything else
falls in the 3-255 range.

Everything works as it should, with only one snag. I cannot access
the modem's web-based setup program. The solution to this is to
connect it directly to one of the workstations. However, this means
the workstation no longer receives an IP address (as the DHCP service
isn't active on the modem) and so it sets its own in the
169.xxx.xxx.xxx range. I cannot connect to the modem on 192.168.1.1,
so I have to manually reset the modem, restoring all its defaults. I
then have to make the changes I want to the settings and configure the
whole thing again!

Its not often admittedly you need to access the modem's setup utility,
but I was experiementing with dynamic dns (which the modem, but
unfortuately not the WiFi router, can handle) and was frustrated
everytime I had to do this. (incidently, I cannot get the dynamic dns
to work when the modem is bridged, maybe somebody knows more than
me??)

So that's the update, I'm not sure there's a solution as in bridge
mode, the ZyXEL modem is no longer part of the IP network it's
delivering the DSL connection and the ISP-assigned internet address to
the 3Com's WAN port, but it no longer has an IP address of its own.
(or am i wrong??)

I'm going to say "many thanks" again (it definitely needs it)
Anonymous
July 20, 2004 6:41:09 AM

Archived from groups: alt.internet.wireless (More info?)

On 19 Jul 2004 12:48:20 -0700, forumemail@eircom.net (FE) wrote:

>I've left the default IP for the router at 192.168.1.1 (when I changed
>it, it wouldn't work!) with the WiFi on 192.168.1.2, everything else
>falls in the 3-255 range.

Impossible. You cannot use the same Class C IP block on both the WAN
port and the LAN port of the same device. Please re-read what I
previously scribbled about NOT re-using the Class C block. That's why
I arbitrarily picked 192.168.5.xxx for the LAN side.

Also, given the choice of using the Zyxel or 3Scum as a router, I
would certainly select the Zyxel as the better devices. However, if
you do that, then the 3Scum will be acting as an access point (bridge)
and not be able to filter by IP address. No big deal as it can filter
by MAC address.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice http://www.LearnByDestroying.com
# jeffl@comix.santa-cruz.ca.us
# 831.421.6491 digital_pager jeffl@cruzio.com AE6KS
Anonymous
July 20, 2004 8:30:52 PM

Archived from groups: alt.internet.wireless (More info?)

"FE" <forumemail@eircom.net> wrote in message
news:6b605e7.0407191148.2acd290@posting.google.com...
> Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message
news:<747mf0tict8k4sg6ggv3nd2bqhjatr20ns@4ax.com>...
> > On 18 Jul 2004 17:19:37 -0700, forumemail@eircom.net (FE) wrote:
> > >
> > >The modem is a ZyXEL Prestige 623R-T1
> > >(ftp://ftp.zyxel.com/P623R-T1/document/P623R-T1_v3-40_Us...)
> > >
>
> Everything works as it should, with only one snag. I cannot access
> the modem's web-based setup program. The solution to this is to
> connect it directly to one of the workstations. However, this means
> the workstation no longer receives an IP address (as the DHCP service
> isn't active on the modem) and so it sets its own in the
> 169.xxx.xxx.xxx range. I cannot connect to the modem on 192.168.1.1,
> so I have to manually reset the modem, restoring all its defaults. I
> then have to make the changes I want to the settings and configure the
> whole thing again!
>
> Its not often admittedly you need to access the modem's setup utility,
> but I was experiementing with dynamic dns (which the modem, but
> unfortuately not the WiFi router, can handle) and was frustrated
> everytime I had to do this. (incidently, I cannot get the dynamic dns
> to work when the modem is bridged, maybe somebody knows more than
> me??)
>
> So that's the update, I'm not sure there's a solution as in bridge
> mode, the ZyXEL modem is no longer part of the IP network it's
> delivering the DSL connection and the ISP-assigned internet address to
> the 3Com's WAN port, but it no longer has an IP address of its own.
> (or am i wrong??)
>
> I'm going to say "many thanks" again (it definitely needs it)

It looks like you're correct that the ZyXel has no IP address of its own
when it's in bridge mode. But there is a solution to the problem of
managing the ZyXel while it's in bridge mode. It's not as pretty as a
web-based GUI. There is a feature called the System Management Terminal.
It's a Command Line Interface that accessible two ways: through Telnet,
which won't help you since this requires an IP address; and by using an
Async connection between a computer's COM port and the ZyXel's PS/2 Console
port. The User Guide only hinted at the existence of a console port, but
the datasheet mentions it. It's not clear, but I believe you'll have to
obtain a DB9-to-PS/2 cable from ZyXel, or make your own. Then you just run
an Async terminal emulator like HyperTerminal, TeraTerm Pro, or something
like that. The commands for the ZyXel are fully documented in the User's
Guide.

Ron Bandes, CCNP, CTT+, etc.
!