Archer C5 V4 Trunk port isse

antoniolcrd · May 14, 2025, 11:48am

Hi everyone,

this archer c5 v4.1 was working fine - 19.07.3 - as a dumb ap with 2 vlans and wan as trunk port for almost a year. Since trunk port failed to communicate tried to fix updating it to update version 24.10 No success. Flashed the 19.07.3 back and set it as a switch instead with uplink via wan port.
I think this issue has relation to the cpu (eth0) wich status is NO LINK since then.
BTW, the gateway router upstream to the internet is a edge router X - 22.03.5 - via untagged port as well.

Would u guys help with some tips before i replace it considering a hw issue?

Thank u in advance.

antoniolcrd · May 14, 2025, 11:59am

Thank u for quicly replying... Will try to manage it setting up the v24.10 again although the communication issue occurred previously in v.19.07.3

Will let you know if succeed.

Rgds.

brada4 · May 14, 2025, 12:12pm

Can you show ip link output (edit away mac addrs) to confirm it is dsa?

antoniolcrd · May 14, 2025, 6:14pm

Sorry my delay. Im in a hurry and updated it to 24.10 And btw, this pop up msg came up: Switch switch0 has an unknown topology - the VLAN settings might not be accurate.:

root@OpenWrt3:~# ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UNKNOWN               qlen 1000
    link/ether b0:xxxxxxxxx brd ff:ff:ff:ff:ff:ff
4: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qle              n 1000
    link/ether b0:xxxxxxxxx brd ff:ff:ff:ff:ff:ff
5: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master               br-lan state UP qlen 1000
    link/ether b0:xxxxxxxxxxxxxx brd ff:ff:ff:ff:ff:ff
6: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state U              P qlen 1000
    link/ether b0:xxxxxxxxx brd ff:ff:ff:ff:ff:ff
root@OpenWrt3:~#```

brada4 · May 14, 2025, 6:27pm

That is swconfig, you will have to check after upgrade. Make backups from working old version. If something breaks unzip tho¡e and type back missing configs.

antoniolcrd · May 15, 2025, 8:04pm

Here u are the old swconfig network v. 19.07 and the current one in v 24.10
Would someone please indicate a new one wich would fix this issue (dsa, vlan and 1-4 ethernet ports)?
i lack of knowledge. Appreciate

the older one v 19.07

config interface 'loopback'
	option ifname 'lo'
	option proto 'static'
	option ipaddr '127.0.0.1'
	option netmask '255.0.0.0'

config globals 'globals'
	option ula_prefix 'XXXXXXXXX:/48'

config interface 'lan'
	option type 'bridge'
	option ifname 'eth0.1'
	option proto 'static'
	option ipaddr '192.168.1.3'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option gateway '192.168.1.1'
	list dns '192.168.1.1'

config device 'lan_eth0_1_dev'
	option name 'eth0.1'
	option macaddr 'XXXXXXX'

config interface 'wan'
	option ifname 'eth0.2'
	option proto 'dhcp'
	option auto '0'

config device 'wan_eth0_2_dev'
	option name 'eth0.2'
	option macaddr 'XXXXXXXX'

config interface 'wan6'
	option ifname 'eth0.2'
	option proto 'dhcpv6'
	option reqprefix 'auto'
	option reqaddress 'try'
	option auto '0'

config switch
	option name 'switch1'
	option reset '1'
	option enable_vlan '1'

config switch_vlan
	option device 'switch1'
	option vlan '1'
	option ports '5t 3 2 1 0 4'

config switch_vlan
	option device 'switch1'
	option vlan '2'
	option ports '5t'

The current one v 24.10

config interface 'loopback'
	option device 'lo'
	option proto 'static'
	option ipaddr '127.0.0.1'
	option netmask '255.0.0.0'

config globals 'globals'
	option ula_prefix 'XXXXXXXXX::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth0.1'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ipaddr '192.168.1.3'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option defaultroute '0'
	list dns '192.168.1.1'
	option delegate '0'
	option gateway '192.168.1.1'

config device
	option name 'eth0.2'
	option macaddr 'XXXXXXX'

config switch
	option name 'switch0'
	option reset '1'
	option enable_vlan '0'

config switch
	option name 'switch1'
	option reset '1'
	option enable_vlan '1'

config switch_vlan
	option device 'switch1'
	option vlan '1'
	option ports '0 1 2 3 7t'

config switch_vlan
	option device 'switch1'
	option vlan '2'
	option ports '4 7t'

config device
	option name 'eth0.1'
	option type '8021q'
	option ifname 'eth0'
	option vid '1'

config device
	option name 'eth0'
	option ipv6 '0'

antoniolcrd · May 19, 2025, 3:05pm

Thank u for helping.

Managed to set etho connected with v 24.10

Im stuck now in add all the 4 eth r45 physical ports to dsa br-lan bridge:

Even if a create a new one (VLAN802.1Q ) luci doesnt reflect its status as active connected link.

Thank you in advance.

psherman · May 19, 2025, 3:30pm

Please reset your C5v4 to defaults. Then out the network config after the reset.

brada4 · May 19, 2025, 3:44pm

Click vlan filter to have them?

psherman · May 19, 2025, 3:49pm

No, I have a feeling that the OP didn't reset to defaults when they upgraded to 24.10 (or they restored their config). As such, it makes the most sense to review the config as it is in the completely default sate/

antoniolcrd · May 19, 2025, 5:14pm

as soon as did lost access to lan interface via luci. But networking still on.

antoniolcrd · May 19, 2025, 5:22pm

Here u are after a new fresh install 24.10 via tftp

config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'xxxxxxx8::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0.1'

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'

config device
        option name 'eth0.2'
        option macaddr 'xxxxxxxx:f8'

config interface 'wan'
        option device 'eth0.2'
        option proto 'dhcp'

config interface 'wan6'
        option device 'eth0.2'
        option proto 'dhcpv6'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '0'

config switch
        option name 'switch1'
        option reset '1'
        option enable_vlan '1'

config switch_vlan
        option device 'switch1'
        option vlan '1'
        option ports '0 1 2 3 7t'

config switch_vlan
        option device 'switch1'
        option vlan '2'
        option ports '4 7t'

what is intended:

set main br-lan as 192.168.1.3 gateway and dns server 192.168.1.1
dhcp, firewall and dns off (dumb ap)
set a br-lan2 as 192.168.20.3 gateway and dns server 192.168.20.1
wan port as a lan port tagged as trunk
vlan 1 (lan 2 lan 3 lan 4)
vlan 2 (lan 1)

Thank u for any assistance.

psherman · May 19, 2025, 5:52pm

Ok... so your device is swconfig based on this default config. This means that you cannot use the DSA syntax to setup your VLANs.

It should be fairly straightforward to do what you want. The logical-to-physical port mapping is shown here.

I assume that this means both vlan1 and vlan2 are tagged on this port. If this is not the case, simply remove the t from one of the VLANs on logical port 4.

This corresponds to logical port 3. We'll remove this from the VLAN 1 stanza and add it to VLAN 2. We'll also be tagging logical port 4 (wan) in both VLAN stanzas. This is what it should look like:

config switch_vlan
        option device 'switch1'
        option vlan '1'
        option ports '0 1 2 4t 7t'

config switch_vlan
        option device 'switch1'
        option vlan '2'
        option ports '3 4t 7t'

Now, we'll remove the wan interfaces -- delete this:

Next, create a new bridge with eth0.2:

config device
        option name 'br-lan2'
        option type 'bridge'
        list ports 'eth0.2'

Now we'll edit the lan:

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ipaddr '192.168.1.3'
	option netmask '255.255.255.0'
	list dns '192.168.1.1'
	option gateway '192.168.1.1'

And we can create the lan2 interface -- but I wouldn't necessarily recommend this particular config (see below):

config interface 'lan2'
	option device 'br-lan2'
	option proto 'static'
	option ipaddr '192.168.20.3'
	option netmask '255.255.255.0'
	list dns '192.168.20.1'
	option gateway '192.168.20.1'

Normally, a bridged AP only uses a single address -- that is, the address needed for managing the device itself. In most cases, the additional interfaces will be 'unmanaged' insofar as the device does not need an address on any other network(s). Specifically, in the case of an iot or guest situation or any untrusted network, the general idea is that those devices should not have any means of connecting to the AP's management interfaces. Instead, they just need a transparent bridge such that the wifi SSID is connected to the upstream router. Assuming that this is your general need, I'd recommend the following instead:

config interface 'lan2'
	option device 'br-lan2'
	option proto 'none'

The only things left will be to disable DHCP on the lan interface. I strongly recommend leaving both dnsmasq and the firewall enabled and running normally. In order to disable the DHCP server, do it explicitly in the config file by setting the lan DHCP server to ignore (option ignore '1') and also remove the IPv6 related entries.

Reboot and you should be good.

antoniolcrd · May 19, 2025, 7:09pm

Thank u man, for a prompt answer.
It headed me back to my first post cos trunk port cant comunicate to trunk port in the main router. clients cant get ip and none communication at all. Besides i can realize some lag using lucy and ssh as well.


root@OpenWrt3:~# cat /etc/config/network

config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'xxxxxxxxx::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth0.1'
        option ipv6 '0'

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option ipaddr '192.168.1.3'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option gateway '192.168.1.1'
        list dns '192.168.1.1'
        option delegate '0'

config device
        option name 'eth0.2'
        option macaddr 'b0:95:75:67:59:f8'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '0'

config switch
        option name 'switch1'
        option reset '1'
        option enable_vlan '1'
        option enable_vlan4k '1'

config switch_vlan
        option device 'switch1'
        option vlan '1'
        option ports '7t 2 1 0 4t'

config switch_vlan
        option device 'switch1'
        option vlan '2'
        option ports '7t 3 4t'

config device
        option type 'bridge'
        option name 'br-lan2'
        list ports 'eth0.2'
        option ipv6 '0'

config interface 'homeland'
        option proto 'static'
        option device 'br-lan2'
        option ipaddr '192.168.20.3'
        option netmask '255.255.255.0'
        option gateway '192.168.20.1'
        list dns '192.168.1.1'

Right now set it back to switch mode (all ports untagged, fixed br lan IP 192.168.1.3 /gateway 192.168.1.1 ) and also switched to a lan untagged port at main router side.

Once i read in this forum abroad the only way to get back v 19.07.03 fully working again is flashing back the original manufacturer fw, reset if and then flash openwrt snapshot and 19.07.3 later. Will try this ASAP before i consider this situation a hw failure maybe.

Will let u know if i succeed.

Appreciate.

psherman · May 19, 2025, 7:18pm

Have you verified your trunk is working as expected? If so, how did you do this? (and for that matter, what is upstream of this OpenWrt device?)

Are both VLANs tagged, or is VLAN 1 untagged on the trunk?

antoniolcrd · May 19, 2025, 7:49pm

i first verified it when the comunnication failed. Then switched connection to a free RJ45 untagged port at upstream side (edge router x) in order discard rj45 port hw problem. There are 2 trunk ports in the main router (eth3T, eth4T )

root@OpenWrt:~# cat /etc/config/network

config interface 'loopback'
        option device 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option packet_steering '1'
        option ula_prefix 'xxxxxxxxx::/48'

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth2'
        list ports 'eth3'
        list ports 'eth4'
        option bridge_empty '1'
        option multicast '0'
        option igmp_snooping '1'
        option ipv6 '0'

config interface 'lan'
        option proto 'static'
        option ipaddr '192.168.1.1'
        option netmask '255.255.255.0'
        option ip6assign '60'
        list dns '1.1.1.1'
        list dns '1.0.0.1'
        option device 'br-lan.10'
        option delegate '0'

config interface 'wan'
        option device 'eth0'
        option proto 'pppoe'
        option username 'xxxx'
        option password 'xxxx'
        option peerdns '0'
        option metric '10'
        option ipv6 '0'
        option auto '0'
        list dns '1.1.1.1'
        list dns '1.0.0.1'

config interface 'wanb'
        option device 'eth1'
        option proto 'dhcp'
        option hostname '*'
        option peerdns '0'
        option metric '15'
        list dns '1.1.1.1'
        list dns '1.0.0.1'
        option delegate '0'
        option force_link '1'

config bridge-vlan
        option device 'br-lan'
        option vlan '10'
        list ports 'eth2:u*'
        list ports 'eth3:t'
        list ports 'eth4:t'

config bridge-vlan
        option device 'br-lan'
        option vlan '20'
        list ports 'eth3:t'
        list ports 'eth4:t'

config bridge-vlan
        option device 'br-lan'
        option vlan '30'
        list ports 'eth3:t'
        list ports 'eth4:t'

config bridge-vlan
        option device 'br-lan'
        option vlan '40'
        list ports 'eth3:t'
        list ports 'eth4:t'

config interface 'homeland'
        option proto 'static'
        option ipaddr '192.168.20.1'
        option netmask '255.255.255.0'
        option device 'br-lan.20'
        option defaultroute '0'
        list dns '192.168.1.1'
        option delegate '0'
        option gateway '192.168.1.1'

config interface 'midia'
        option proto 'static'
        option ipaddr '192.168.30.1'
        option netmask '255.255.255.0'
        option device 'br-lan.30'
        option defaultroute '0'
        list dns '192.168.1.1'
        option delegate '0'
        option gateway '192.168.1.1'

config interface 'iot'
        option proto 'static'
        option ipaddr '192.168.40.1'
        option netmask '255.255.255.0'
        option device 'br-lan.40'
        option defaultroute '0'
        list dns '192.168.1.1'
        option delegate '0'
        option gateway '192.168.1.1'

config interface 'zerotier'
        option proto 'none'
        option device 'ztrfyj5aia'
        list dns '192.168.1.1'
        option delegate '0'

config device
        option name 'ztrfyj5aia'
        option ipv6 '0'

config device
        option name 'br-lan.10'
        option type '8021q'
        option ifname 'br-lan'
        option vid '10'
        option multicast '0'
        option ipv6 '0'

config device
        option name 'br-lan.20'
        option type '8021q'
        option ifname 'br-lan'
        option vid '20'
        option ipv6 '0'

config device
        option name 'br-lan.30'
        option type '8021q'
        option ifname 'br-lan'
        option vid '30'
        option ipv6 '0'

config device
        option name 'br-lan.40'
        option type '8021q'
        option ifname 'br-lan'
        option vid '40'
        option ipv6 '0'

psherman · May 19, 2025, 8:16pm

Let's fix up some things in your ER-X:

Delete the lines marked with -:

antoniolcrd:

config device
        option name 'br-lan'
        option type 'bridge'
        list ports 'eth2'
        list ports 'eth3'
        list ports 'eth4'
-        option bridge_empty '1'
-        option multicast '0'
-        option igmp_snooping '1'
-        option ipv6 '0'

Similarly:

antoniolcrd:

config interface 'lan'
        option proto 'static'
        option ipaddr '192.168.1.1'
        option netmask '255.255.255.0'
        option ip6assign '60'
-        list dns '1.1.1.1'
-       list dns '1.0.0.1'
        option device 'br-lan.10'
-      option delegate '0'

Now on the other interfaces:

antoniolcrd:

config interface 'homeland'
        option proto 'static'
        option ipaddr '192.168.20.1'
        option netmask '255.255.255.0'
        option device 'br-lan.20'
        option defaultroute '0'
-        list dns '192.168.1.1'
-        option delegate '0'
-        option gateway '192.168.1.1'

config interface 'midia'
        option proto 'static'
        option ipaddr '192.168.30.1'
        option netmask '255.255.255.0'
        option device 'br-lan.30'
        option defaultroute '0'
-        list dns '192.168.1.1'
-        option delegate '0'
-        option gateway '192.168.1.1'

config interface 'iot'
        option proto 'static'
        option ipaddr '192.168.40.1'
        option netmask '255.255.255.0'
        option device 'br-lan.40'
        option defaultroute '0'
-        list dns '192.168.1.1'
-        option delegate '0'
-        option gateway '192.168.1.1'

Delete this:

antoniolcrd:

config device
        option name 'br-lan.10'
        option type '8021q'
        option ifname 'br-lan'
        option vid '10'
        option multicast '0'
        option ipv6 '0'

config device
        option name 'br-lan.20'
        option type '8021q'
        option ifname 'br-lan'
        option vid '20'
        option ipv6 '0'

config device
        option name 'br-lan.30'
        option type '8021q'
        option ifname 'br-lan'
        option vid '30'
        option ipv6 '0'

config device
        option name 'br-lan.40'
        option type '8021q'
        option ifname 'br-lan'
        option vid '40'
        option ipv6 '0'

Once all of that is done, reboot the ER-X and test again.

But with that said, we haven't reviewed your DHCP and firewall files. How have you verified that the additional VLANs are working as expected?

antoniolcrd · May 20, 2025, 1:15am

Humm. Thank you for yr approach.
Will read it carefully before take any action (noob here). As i first said it was working properly for almost a year ( ER-x as main router with upstream to internet and 2 trunk links to archer C5 and archer C6 - 4 vlans) Till the C5 trunk began to fail... Also will consider try it next weekend and avoid network downtime. C6 covers iot and media stuff. C5 was covering a small office and still does as a regular switch.
Will share ASAP.

Rgds,

antoniolcrd · May 20, 2025, 1:26am

Regarding fw and dhcp:

Firewall overview:

DHCP server on each vlan interface (192.168.1.X [home-lan] 192.168.20.x [homeland] 192.168.30.x [media] 192.168.40.x [ iot]

psherman · May 20, 2025, 2:46am

Do you have firewall rules to allow DHCP and DNS (you currently reject or drop input in the firewall).

Please connect to your OpenWrt device using ssh and copy the output of the following commands and post it here using the "Preformatted text </> " button:

Remember to redact passwords, MAC addresses and any public IP addresses you may have:

ubus call system board
cat /etc/config/dhcp
cat /etc/config/firewall