Author Topic: Cannot access show router iva wire from home router  (Read 248 times)

Offline jnealand

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Cannot access show router iva wire from home router
« on: June 24, 2019, 09:11:04 AM »
Rick Harris and I fought this problem yesterday for way too long.  Both of us have two routers - a home router and a show router.  The WAN port on the show router is connected to a LAN port on the home router via cable.  The show routers have static IPs that are not within the DHCP ranges. Rick uses different routers than I do.  A total of 3 different branded routers are being used here.  We can ping the the show router from the home network and show router also shows up using ipscanner.  We have routes setup and can access FPP setups and even F16s attached to a Pi.  However, we can not access the show router ip from a web browser in order to access the routers configuration pages.  We are not blown out of the water since we can access the show router via wifi and access the routers configuration pages, so this is an educational question more than a critical need.  The error we both get is a timed out error - see attached screenshot.

What could be preventing the show router admin interface from being accessed via cable from the home network when all other active IPs on the show network are accessible?????
Jim Nealand
Kennesaw, GA all Falcon controllers, all 12v Master Remote Multisync with Pi and BBB P10 and P5

Online Poporacer

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Re: Cannot access show router via wire from home router
« Reply #1 on: June 24, 2019, 01:22:51 PM »
Just to provide additional information, here are my specifics:

Home router
IP: 192.168.0.1 (DHCP Server allocation begins at 192.168.0.20)

Show Router
Internet IP (static address): 192.168.0.2
Internet subnet mask: 255.255.255.0
Internet Gateway: 192.168.0.1
Internet DNS Server: 192.168.0.1

LAN IP (static address): 192.168.1.1
LAN subnet mask: 255.255.255.0

Wireless SSID and Password set.

Home Router has Static Route entered:
route 192.168.1.0 255.255.255.0 192.168.0.2 (This isn't the route add command, just the specifics of the static route)

Here is the behavior:
I am accessing the networks via a laptop with a wireless connection.
There are no static routes saved on the computer
If I go to attached devices on the home router, it shows the show router connected at 192.168.0.2

If I log into the wireless connection of the home router, I cannot access the show router or any of the attached devices.
I cannot access the web UI of the show router through the address of 192.168.0.2 or 192.168.1.1
I cannot ping the Show router
tracert of 192.168.0.2 results in "request timed out", it does not look like it is going to the home router.

If I log into the wireless connection of the Show Router, I can access the show router via 192.168.1.1 and 192.168.0.2
I can access the Home Router at 192.168.0.1
I can access the internet.
All of my show components have access to the internet.

It looks like the network traffic isn't working going through the home router to the show router but it is working going from the show router to the home router and then to the internet?




« Last Edit: June 24, 2019, 01:49:21 PM by Poporacer »
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Offline pixelpuppy

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Re: Cannot access show router iva wire from home router
« Reply #2 on: June 24, 2019, 01:55:24 PM »
Most home WiFi routers are NAT router and not true full routers.   This usually means that you can't initiate a connection from the "outside" (wan side) to the "inside" (lan side).    They are primarily intended for connections that are initiated from the home (lan side) out to the internet (wan side).   Its a security feature to prevent the dark web from probing your home network.


With that said, some brands will let you configure them to allow certain traffic (and web access to the configuration gui) from the wan side but its usually not enabled be default.  Sometimes, this also requires (or optionally allows) HTTPS for secure connections. Also, many models can be converted or flashed with open router software like DDWRT or TOMATO.  Running that firmware will let you set them up as true routers and not just NAT boxes
-Mark

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Re: Cannot access show router iva wire from home router
« Reply #3 on: June 24, 2019, 02:10:49 PM »
And how can you tell if it is a NAT router and not a full router? It appears that I can set things up correctly. My home router is a Zyxel C3000Z and my show router is a Netgear WNDR3700v3
Most home WiFi routers are NAT router and not true full routers.   This usually means that you can't initiate a connection from the "outside" (wan side) to the "inside" (lan side).
So the problem is with the show router? If so, why does the tracert to 192.168.0.2 not show traffic going to the home router first?

Offline pixelpuppy

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Re: Cannot access show router iva wire from home router
« Reply #4 on: June 24, 2019, 02:29:07 PM »
And how can you tell if it is a NAT router and not a full router? It appears that I can set things up correctly. My home router is a Zyxel C3000Z and my show router is a Netgear WNDR3700v3
A full router runs routing protocols like RIP, BGP OSPF, EIGRP, IS-IS, etc.  If your router has no setup or configuration for any of these routing protocols then its not a full router.   When I said "most home wifi routers" I really meant virtually all home off-the-shelf wifi routers versus higher-end commerical routers (like Cisco or Ubiquity) that some people run in their homes.   The two you mentioned are off-the-shelf home WiFi routers that use NAT.  You can still make it work but you will need to configure it for port forwarding in order to initiate a connection on the WAN side that passes through to the LAN side.   And then you would access devices using network PORT instead of network ADDRESS   i.e. 192.168.0.2:1003 to get to 192.168.1.3 using a port forwarding table that maps port 1003 to inside address 192.168.1.3

Quote
So the problem is with the show router? If so, why does the tracert to 192.168.0.2 not show traffic going to the home router first?
Yes, the problem is the show router is not a full router.  Its a NAT router AND it has basic firewall rules that block things like tracert and HTTP.  AND by default it blocks gui access from the WAN side, but you can usually enable that somewhere in the setup

To do what you want, you really want to look at open software like DD-WRT (dd-wrt.com).  You can run it on the Netgear router, but I don't think there is a version that works with the Zyxel (not sure though)

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Re: Cannot access show router iva wire from home router
« Reply #5 on: June 25, 2019, 12:01:43 AM »
If the problem is accessing the LAN from the WAN then the only router that would need to be modified would be the show router, correct? If so, do I install the DD-WRT software and just set up the routing in there? (I will try and research it as well)
I find it odd that the tracert didn't even make it to the home router?

Offline pixelpuppy

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Re: Cannot access show router iva wire from home router
« Reply #6 on: June 25, 2019, 07:52:04 AM »
If the problem is accessing the LAN from the WAN then the only router that would need to be modified would be the show router, correct? If so, do I install the DD-WRT software and just set up the routing in there? (I will try and research it as well)
yes

Quote
I find it odd that the tracert didn't even make it to the home router?
Its because the path from your PC at 192.168.0.x to the show router at 192.168.0.2 is on the same subnet and so the packets don't get routed  The home router will route the packets when they need to get out to the internet.
In other words, A router is used to pass traffic from one subnet to another subnet. Systems on the same subnet will talk directly to each other without using a router.
« Last Edit: June 25, 2019, 08:02:45 AM by pixelpuppy »

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Re: Cannot access show router iva wire from home router
« Reply #7 on: June 25, 2019, 08:57:17 AM »
Its because the path from your PC at 192.168.0.x to the show router at 192.168.0.2 is on the same subnet and so the packets don't get routed  The home router will route the packets when they need to get out to the internet.
In other words, A router is used to pass traffic from one subnet to another subnet. Systems on the same subnet will talk directly to each other without using a router.
IC, that makes sense. So it should be as simple as installing DD-WRT on my Show router? No other setup for the two networks to communicate?
Then of course in order to access the other subnets on the Show network, I will need to setup routing in the show router and the home router?

Thanks a million for the information!

Offline pixelpuppy

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Re: Cannot access show router iva wire from home router
« Reply #8 on: June 25, 2019, 10:24:45 AM »
So it should be as simple as installing DD-WRT on my Show router? No other setup for the two networks to communicate?
Not quite that simple, but its not overly complicated.   You will need to setup/configure DD-WRT for your particular network environment.  Its not much more than basic IP configuration for the two interfaces (WAN side and LAN side).  And, of course, your home router will still need static routes for any and all subnets behind the show router

 

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