[TriLUG] Network configuration help?

[Joseph Mack NA3T via TriLUG]

On Mon, 3 May 2021, Brian McCullough via TriLUG wrote:

> OK, so I THINK that I got the configuration of the VLAN ( #2 ) set up on 
> the OpenWRT machine, with that interface marked as Tagged and attached 
> only to VLAN2.

I think your OpenWRT machine is the main router, which connects to your 
ISP.

> When I plug a device into that port, the OpenWRT DHCP assigns it an 
> address.  Fine, so far.

for discussion, give us the address range. I assume it's not 
192.168.1.0/24, since that's the address range of the ZyXEL LAN.

> The other end of that cable is plugged into one of the four ports on the 
> ZyXEL.
>
> DHCP is turned off on the ZyXEL.

good.

> Before I plugged that cable in, I set up the WiFi configuration on the
> ZyXEL with my laptop.  The laptop address was assigned by the ZyXEL's
> DCHP before I turned that off.

The WAP (here the ZyXEL) on the LAN side has its own static IP (likely 
192.168.1.1, which you can set through the configuration page). The 4 LAN 
ports are a switch. They don't have IPs. There is only 1 IP on the LAN 
side of the WAP (192.168.1.1).

I suggest that you don't change that IP. Someone in the far distant future 
(likely you) might have to see why this WAP is not behaving and unless you 
want to write the new address on the side of the WAP, you want to be able 
to get into the box after disconnecting it from the network. You may have 
to reset it to defaults (by pressing the button on boot), and you would 
like it to have the same IP after resetting. I have a script on my laptop 
which adds 192.168.1.253 to my ethernet card and for good measure fires up 
dhcpd on that address. Thus anything I plug into my laptop, is likely to 
come up pingable.

Set up your ZyXEL (SSID, turn off dhcpd) from the laptop. Now check that 
another wifi client can associate with the ZyXEL SSID and get an IP (from 
the laptop). You ZyXEL is now setup.

Setup the main router to dhcpd addresses on a different network, say 
192.168.2.0/24. You will have to change the IP on the LAN side of your 
main router, to say 192.168.2.253. (Since machines that you buy all come 
configured with IPs x.x.x.1, I try not to have any of my machines with an 
address x.x.x.1.). Connect a port on the LAN side of the main router to 
the LAN side of the ZyXEL. There is no network connection between the 
192.168.2.0/24 on the main router to the 192.168.1.1 on the ZyXEL. The 
192.168.1.1 is only there if you ever want to mess with the ZyXEL. wifi 
clients connecting through the ZyXEL associate with the SSID and the WAP 
acting as a bridge broadcasts the dhcp request out its 4 LAN ports. The 
address 192.168.1.1 on the WAP is not involved since no dhcpd is running 
on it. The home router hands the wifi client an address in the 
192.168.2.0/24 range. You're done.

If you want to add a 2nd ZyXEL, you leave it on 192.168.1.1 too, with 
dhcpd turned off. You could have a mess of ZyXELs all on 192.168.1.1.  The 
home router won't know about them (being on 192.168.2.0/24). You could 
have 4 ZyXELs all with 192.168.1.1 all connected to the switch on the LAN 
side of your home router. Maybe they arp now and again, but they don't 
cause any problems and you know that when you want to mess with them, they 
all have the same IP.

> The configuration on the ZyXEL wants the "LAN" to have an IP address. Do
> I set it to the same address as was assigned from the OpenWRT DHCP?

I assume I've answered that.

> What about the other three ports on the ZyXEL?  At least during setup, I
> want to plug my laptop into there to work on the ZyXEL configuration.

make sure you leave 192.168.1.1 on the ZyXEL. If there's no other machine 
with 192.168.1.1 on the network, you should be able to mess with the ZyXEL 
from a laptop with a static IP (like 192.168.1.252). If you have a bunch 
of machines on 192.168.1.1, just unplug the one you want to mess with.

> At present, with "192.168.1.252" assigned by the OpenWRT box, and, by
> default, "192.168.1.1" assigned to the "LAN" by the ZyXEL, I have no
> communication from the ZyXEL outwards.

make the 192.168.1.252 static. Also make sure the main router isn't having 
IP address collisions with the ZyXEL or your laptop. Move it to another 
neetwork.

> I attempted to add a Static Route for Default on the ZyXEL, pointing it
> to the LAN address, but that was not accepted.

by which box? What was the error mesg?

Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) trilug (dot) org - azimuthal equidistant
map generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!