Basics on Wifi Bridge

I am a total OpenWRT newb, so forgive me if this message comes across as stupid.

I have got OpenWRT working on a couple of routers, the plan was to create a wifi bridge

A friend gave me an old TPlink and it works albeit that signal is not great so I thought I would get some better routers, install OpenWRT and see if I could improve things.

I understand that a new install does not set wifi on and that makes sense and I think I understand that I need to scan for a wifi to connect to in client mode (my preferred method), and then I need to create a second wifi which is called Master in OpenWRT terminology.

However, when I do this I get ---/-101 dBm with no internet connection.

Is this just an inadequate signal or is there something I can do?

Can someone also explain to me what dBm is and how what are the two numbers -60/-95 dBm relevant and why are they negative?

Also what is MCS?
What are good and bad examples of MCS

It would be great if someone could explain the “layers” of OpenWrt, in my logic it would be from bottom up

Wifi
Interface
Switch

Are there any “must do” things in these three?

The other thing is that when I compare the interfaces firewall settings they are not in the same order, does this matter and how should they be laid out?

Generally you'd try everything out in the same room so signal strength isn't an issue. Then deploy the equipment to where it will be used.

OpenWrt won't increase radio range or performance compared to stock firmware, but it gives you more operational modes like client mode, mesh and WDS.

If you're connecting to a regular AP (e.g. your neighbors or a public network) you'd use a routed client, if you own the AP and can set it to WDS or mesh then you can have a true bridge.

The default firewall routing from LAN to WAN is suitable for a routed client, since you're just replacing the wired Internet connection with wireless. Bridged configurations have only one network, the LAN, and there is no firewalling involved.

1 Like

According to your description, WDS/ 4addr should be the preferred/ preferable solution:

1 Like

Thanks for your good advice.

It is for a public network, I have ascertained that Client mode is the only one that works with this vendor.

My networking expertise is probably way below that of most people here although I have installed some quite complex networks in some projects.

What I am not clear on is ground rules, I have established that wifi is not setup by default, but are there other must do tasks?

Is WAN on the Switch only meaning the hardware WAN port, should I delete it if not used to keep things simple (the one that works does not have a row for it).

Working router has the following on switch screen, others I have tried do not

Enable learning and aging

I must admin the Interfaces screen throws me, they are not in same order, not named the same and I can't seem to replicate the underlying settings.

For example the one that works does not have the WAN port tagged, yet there is a green WAN interface and a RED WWAN interface, no idea as to the significance of these, I have seen purple and orange in videos online.

Is it the case that one can install OpenWrt, locate the router close to one that already works, scan for wifi's to Bridge/Repeat, then configure a Master Wifi or connect another router and that should give you Internet connection, or are there some schoolboy errors or steps I might have missed?

What throws me is that you have an interface such as WAN but in the config it has a definition also called interface defined as eth0.2, a Software VLAN (wan). While Lan is has the interface under physical defined as Interface

x [Switch VLAN: "eth0.1"] eth0.1
x [Wireless Network: Master "MyWifi"] radio1.network1

WWAN is the defined as [Wireless Network: Client "OpenWi-fi"] wlan0

Then we have firewall settings, they are different on both devices and hard to replicate.

These are all the config of the working router, some of them use what appear by TX RX to be inactive but they are in the firewall setup

Create / Assign firewall-zone

wan wan6: (empty) VPN: [Ethernet Adapter: "tun0"] wwan: [Wireless Network: Client "OpenWi-fi"] AT6B5C: (empty)MeLofi: (empty)

Does the fact that is says Create/Assign firewall-zone mean it has not been done yet?

This is the config of the working router, you can see from the TX RX numbers where the data is going.

WORKING ROUTER

AT6B5C (Red)
Device: Not present
Connected: no
Not present
Protocol: DHCP client
Error: Network device is not present

MYLOFI (Red)
Device: Not present
Connected: no
Not present
Protocol: DHCP client
Error: Network device is not present

VPN (Red)
Type: Ethernet Adapter
Device: tun0
Connected: no
RX: 0 B (0 Pkts.)
TX: 0 B (0 Pkts.)
tun0
Protocol: Unmanaged
RX: 0 B (0 Pkts.)
TX: 0 B (0 Pkts.)
Information: Not started on boot

LAN (Green)
Type: Bridge
Device: br-lan
Connected: yes
MAC: 00:00:00:00:00:00
RX: 6.83 GB (46668246 Pkts.)
TX: 151.01 GB (122464925 Pkts.) (Type: Software VLAN
Device: eth0.1
Connected: yes
MAC: 00:00:00:00:00:00
RX: 6.83 GB (46668251 Pkts.)
TX: 151.01 GB (122464925 Pkts.)Type: Wireless Adapter
Device: radio1.network1
Connected: no
RX: 0 B (0 Pkts.)
TX: 0 B (0 Pkts.))
br-lan
Protocol: Static address
Uptime: 17d 20h 42m 24s
MAC: 00:00:00:00:00:00
RX: 6.83 GB (46668246 Pkts.)
TX: 151.01 GB (122464925 Pkts.)
IPv4: 192.168.5.1/24
IPv6: fd02::1/60

WAN (Green)
Type: Bridge
Device: br-wan
Connected: yes
MAC: 00:00:00:00:00:00
RX: 0 B (0 Pkts.)
TX: 856 B (8 Pkts.) (Type: Software VLAN
Device: eth0.2
Connected: yes
MAC: 00:00:00:00:00:00
RX: 0 B (0 Pkts.)
TX: 856 B (8 Pkts.))
br-wan
Protocol: Static address
Uptime: 17d 20h 42m 24s
MAC: 00:00:00:00:00:00
RX: 0 B (0 Pkts.)
TX: 856 B (8 Pkts.)
IPv4: 192.168.4.254/24

WAN6 (Red)
Device: Not present
Connected: no
Not present
Protocol: DHCPv6 client
Error: Network device is not present

WWAN (Red)
Type: Wireless Adapter
Device: wlan0
Connected: yes
MAC: 00:00:00:00:00:00
RX: 17.67 GB (13892121 Pkts.)
TX: 679.10 MB (4601792 Pkts.)
wlan0
Protocol: DHCP client
Uptime: 1h 11m 59s
MAC: 00:00:00:00:00:00
RX: 17.67 GB (13892121 Pkts.)
TX: 679.10 MB (4601792 Pkts.)
IPv4: 100.111.111.111/16

I tried WDS on OEM firmware on about 5 routers before I realised WDS did not work with this provider, I have used WDS myself to connect routers where I lived, but this one only works in Client mode and only on OpenWRT, there was something in DD-WRT that prevented it from working, but on OpenWRT I have an old router on which it works, so now I want to use a better Router and also get my head around what is "under the hood".

The color in the interface status screen is the firewall zone. The default two zones are lan (green) and wan (red). wan is red to indicate that it is the Internet and there are things there that are not trustworthy.

For setting up a routed client to connect to the Internet from a public AP I'd do the following.

Install OpenWrt or reset OpenWrt to default settings. Log in with a wired connection to the lan port.
Conduct a wifi scan. If the AP signal strength is lower (more negative than) -80, stop. There isn't enough signal for reliable operation. Relocate the router or replace with better hardware, antenna, etc.
Finding signal is OK, continue. Make note of the network name and close the scan window. Do NOT click the "Join Network" button.
Go to wifi and edit the default interface, which is an AP. Change it to client. Set ESSID to the name of the network. Set network to wan. Leave BSSID blank. Configure encryption if necessary.
Go to Network Interfaces edit wan and check the physical settings. The wifi client should be the only thing there. The Bridge box must not be checked.
Go to the main status and see if you have an IPv4 upstream. If the address is something other than 192.168.1.X, you should be online at this point.
If the WAN IP is 192.168.1.X, you need to change the LAN IP to something outside that range, like 192.168.2.1.

As I said it should now be online with a wired connection. Further optional tweaks are to add a wireless AP creating a repeater, and to re-purpose the WAN ethernet port so you can hook up an additional wired device. (Right now, the WAN port isn't logically connected to anything, since you took the ethernet out of the wan network and made it wireless).