Basic misconception of how to use the ports

Installing and Using OpenWrt
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My question might very probably sound silly, but I'm asking nevertheless because some things are not working as I think they should do and I want to clarify at least basic concepts of OpenWrt.

I guess I've been under the misconception of how to use the ports. I'm running OpenWrt on a Linksys MR8300. Its 5 ports are labeled from left to right: Ethernet 1 to 4 and Internet. I always was of the opinion that the modem goes into the WAN port labeled Ethernet and everything else can go into any other port. Isn't that true?

Network > Interfaces shows LAN, WAN and WAN6. I added another Interface for WIRELESS. Devices are br-lan, eth0 and eth1.

What's then the matter about eth0 beeing the hard wired connection from CPU to the internal switch? Is there a "special" port to access the device only for management tasks? Is it maybe something you can and should configure seperately?

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I'm no expert, but to put is simply. For the MR8300, similar to EA8300, eth1 is the physical WAN port. eth0 represents the LAN ports, by openwrt default.

br-lan is used to make multiple virtual or physical network interfaces act as if they were just one network interface. In your case the 4 ports and wifi are part of br-lan by 'default'. ie. the 'LAN'.

Someone will correct me if I'm wrong.

You may notice there is no WAN port in the LuCI switch menu of 21.02 for your MR8300. Perhaps that's why you are getting confused?

There are strange switch issues with IPQ40xx devices.
https://forum.openwrt.org/t/ipq40xx-switch-config-strangeness/32542

I have a IPQ4018 EA6350v3 as a openwrt vpn router. I have the ethernet port functions reversed. ie. the 4x labelled LAN ports are my WAN port and the labelled WAN is my LAN port.

update: I had eth0 and eth1 functions reversed. Now corrected
update 2: I was right the first time. wan is eth1.

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The eth0 interface connects the CPU with the WAN port; the eth1 interface connects the CPU with the internal switch where all LAN ports are connected.

Your modem should be connected to the WAN port, and all your devices to the LAN ports.

The "br-lan" device bridges all the LAN ports with the WLAN devices.

There is no management port, unless you configure one explicitly.

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I see. You are talking about one LAN port altough there are four of them. So they ARE interchangable. eth0 is referring to all 4 LAN ports. Thanks for the clarification.

That was the solution I originally I wanted to achive. I had to manually add wlan0, wlan1 and wlan2 to br-lan. Now I have access to the router and to the internet from my phone. Thanks a lot!

Now my only fear left is that I'm accidentally exposing my LAN to WAN or there is some other security related issue. Isn't there a guideline of what has to be checked?

Thanks again! :slight_smile:

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@bill888 @eduperez
Both of you claimed that eth0 is the wan port and eth1 are the lan ports. This is not true in my case. Here are some values right from the page:

Interfaces:
LAN
br-lan (eth0,wlan2)

WAN
eth1

WAN6
eth1

WIRELESS
wlan2

Just as a clarification for anyone else with a Linksys MR8300.

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You are correct.

I just rechecked 'default' openwrt config for my ea6350v3.

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth0'

config interface 'wan'
	option ifname 'eth1'
	option proto 'dhcp'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ipaddr '192.168.1.1'
	option netmask '255.255.255.0'
	option ip6assign '60'

ie. I was right the first time. Confusion arose because I transposed the ports (ie. 4x WAN + 1x LAN) on my live ea6350v3, and I read eduperez's post.

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Yes, I mixed the eth ids, sorry.

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