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IPv4 address query

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al1q
IPv4 address query

Good evening!

We are working with mesh net in our club, and set up a test network.  The results are not what we expected, but no one has much experience with networking.  I'm curious as to why we got the results we did.  The idea was to set up a local network with file sharing, with access to services on other nodes.

We set up an access point using a NanStation M2 on channel 1, with a dtd connection to a NanoStation M2 on channel -2.  We also had an AirRouter on Channel -2 with a Raspberry Pi connected to it.  There were no other connections to the network.  All network settings on the NanoStation and AirRouter were left on AREDN default.

We then connected several laptops by WiFi to the network, pulled up the DOS command window, and ran ipconfig, followed by PINGing each other.  All of the computers were on the same subnet (255.255.255.248), but there were two different gateways:

GW #1: 10.245.255.185
GW #2: 10.245.245.41

Perhaps not surprisingly,  we couldn't ping all of each other -- the command either timed out, or it was an unreachable address.  The address of the computers were:

10.245.245.46
10.245.245.42
10.245.245.43
10.245.255.187
10.245.255.190
.
The Raspberry Pi had a static IP address (it ran Mesh Chat), offered as a service on the AirRouter,  and could be accessed by all the laptops (plus a few smartphones).  The laptops ran with a dynamic IP (running both Windows 7 and Windows 10, if that makes any difference).  10.245.245.## and 10.245.255.### could not ping each other.

Clearly, our set up was not ideal, and we need to get a better grasp on network addressing.  Is having two gateways with one access point normal?  That seems counterintuitive.  What would cause that?  And would the two gateways lead to the differing IP addresses?  

Would anyone have suggestions on how to set up a single gateway?  

Thank you!

Jeff Stidham, AL1Q



 

K6CCC
K6CCC's picture
You're not on the same subnet

Sounds like the LAN connection from multiple AREDN devices are on the same physical network.  What is happening is that both AREDN devices are acting as a DHCP server and some of your devices are getting DHCP assignments from one AREDN device and some are getting DHCP assignments from another one.  Ideally you want only one device acting as a DHCP server on a LAN.  Having two will cause problems.  Honestly, I'm not awake enough to walk you through the required changes without being able to look at my AREDN nodes (really late night last night and only four hours of sleep).
 

al1q
"You're not on the same subnet"

Thank you.  As I said, we didn't mess with the default network settings for the set up, so that shows where to look.  

73, Jeff

nc8q
nc8q's picture
IPv4 address query

Hi, Jeff:

You did not mention a switch. I am guessing (like K6CCC) that you have more than one node connected to the same LAN device
(a dumb switch?). If these two nanostations are not locos, then feed the node NSM2 with 'Pass through POE' and let the WiFi'ed
NSM2 be the sole DHCP server. If you have 5 (or more) computers (or devices) that will need a DHCP client address, you should
set your (WiFi'ed) node to 13 (or 29 if needed) hosts. The node itself consumes an address.

Else, each NODE's LAN connects to a separate physical switch.

Else, each NODE's LAN connects to a different VLAN on a 'managed' switch (802.1Q).

255.255.255.248 is a netmask.
10.245.245.41/29 is a subnet.
10.245.255.185/29 is a subnet.

You mention that the RPi (MeshChat server) has a static address.
You might consider letting it get a DHCP address from the AirRouter, then
reserving that address on the AirRouter, then
advertising that service on the AirRouter. Then, ...
If the NSM2-node gets a (RF or DtD or tunnel) link to the AirRouter,
you will be able to ping the RPI by name or IP address
from any connected device (computer).

I hope this helps, Chuck

al1q
'Pass through POE'

Good afternoon, Chuck!

Thank you, that helped a lot.  

There is no switch.  The NanoStations (not locos) are linked dtd through the secondary ports.  Is there a difference in using the "Pass through POE"?  I didn't see any in the documents I read.

Following K6CCC's advice, I set up only one DHCP (the access point (the "WiFi'ed NSM2"), in fact), and that cleared up the two subnets.  

After viewing Darryl's video, your advice about the RPI makes sense, and we'll give that a go.    The same thing for your advice about increasing the number of hosts.

73, Jeff

K5DLQ
K5DLQ's picture
This may help explain

This may help explain connections with a switch and without....   https://www.arednmesh.org/content/understanding-vlans
 

al1q
Thank you, that clarified

Thank you, that clarified things a lot.

73, Jeff AL1Q

Ai6bx
I also note

I also note that you mention connecting all laptops via WiFi but made no mention of a mesh access point. A mesh AP would have its dhcp server turned off so it assigns LAN IP addresses from the node it is connected to. Note the LAN IP is different than the node IP addresses. I may have missed mention of an AP so if I did, forgive me. Typically this would be connected to the switch mentioned by Jeff above. I typically use Tough Switches for my sites and would plug a LAN port of the AP into a LAN assigned to one of the connected nodes. 

OK, I did see you mention having a NS M2 as an access point. Would I be correct that this is still running Ubiquiti firmware or did you flash with a version of AREDN? 

I hope this helps.

al1q
"I also note"

I flashed the NSM2 with AREDN v3.19.3.0, and then configured it as an Access Point, and designated it as a DHCP server as well.  I also increased the number hosts to 13, as per Chuck.  

It's working more like we expected, although the current set up only has two laptops.  A repeat performance of the earlier test is planned shortly.

Thank you!

 

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