LAN port not working on TP-Link Archer A6 v3

Appetite2 · February 28, 2025, 6:41am

After updating to openwrt 24.10.0 yesterday, my linux computer (connected using a LAN cable) could no longer get a DHCP lease from the router.

I spent 6 hours trying to debug it, not knowing exactly what the problem was. I tried static DHCP lease on the router. I tried setting a static IP on the computer using nmcli. Tried power cycling both the devices multiple times. Tried plugging in the LAN cable into all the different ports.

The computer used to connect without a problem before. My WiFi devices continued to connect after the upgrade. So it looks like something wrong with the LAN on the 24.10.0 firmware.

Reverting to OpenWrt 23.05.5 fixed the issue immediately. I am not sure what the problem is, but just thought I'd put it out there for anybody else facing this issue after the upgrade. I will probably try to upgrade when a newer firmware is out, just to see if anything is fixed.

psherman · February 28, 2025, 6:48am

Let's take a look at your configuration.... is it safe to assume that you kept the configuration when you did the upgrade?

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/network
cat /etc/config/wireless
cat /etc/config/dhcp
cat /etc/config/firewall

mietekn · February 28, 2025, 2:45pm

Please attach the kernel log here.

Appetite2 · March 13, 2025, 8:00am

Yes I did retain the configuration when I did the upgrade.

root@OpenWrt:~# ubus call system board
{
	"kernel": "6.6.73",
	"hostname": "OpenWrt",
	"system": "MediaTek MT7621 ver:1 eco:3",
	"model": "TP-Link Archer A6 v3",
	"board_name": "tplink,archer-a6-v3",
	"rootfs_type": "squashfs",
	"release": {
		"distribution": "OpenWrt",
		"version": "24.10.0",
		"revision": "r28427-6df0e3d02a",
		"target": "ramips/mt7621",
		"description": "OpenWrt 24.10.0 r28427-6df0e3d02a",
		"builddate": "1738624177"
	}
}

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 ula_prefix 'changed:this:abcd::/48'
	option packet_steering '1'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'lan1'
	list ports 'lan2'
	list ports 'lan3'
	list ports 'lan4'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ipaddr '192.168.0.1'
	option netmask '255.255.255.0'
	option ip6assign '60'

config interface 'wan'
	option device 'wan'
	option proto 'dhcp'
	option peerdns '0'
	list dns '9.9.9.9'
	list dns '149.112.112.112'

config interface 'wan6'
	option device 'wan'
	option proto 'dhcpv6'
	option reqaddress 'try'
	option reqprefix 'auto'

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

config wifi-device 'radio0'
	option type 'mac80211'
	option path '1e140000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0'
	option channel '1'
	option band '2g'
	option htmode 'HT20'
	option disabled '1'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option network 'lan'
	option mode 'ap'
	option ssid 'OpenWrt'
	option encryption 'none'

config wifi-device 'radio1'
	option type 'mac80211'
	option path '1e140000.pcie/pci0000:00/0000:00:01.0/0000:02:00.0'
	option channel '36'
	option band '5g'
	option htmode 'VHT80'
	option cell_density '0'
	option country 'SE'

config wifi-iface 'default_radio1'
	option device 'radio1'
	option network 'lan'
	option mode 'ap'
	option ssid 'myssid_5ghz'
	option encryption 'psk2'
	option key 'mypassword'

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

config dnsmasq
	option domainneeded '1'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option local '/lan/'
	option domain 'lan'
	option expandhosts '1'
	option cachesize '1000'
	option authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option localservice '1'
	option ednspacket_max '1232'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'
	list dhcp_option '6,9.9.9.9,149.112.112.112'

config dhcp 'wan'
	option interface 'wan'
	option ignore '1'

config odhcpd 'odhcpd'
	option maindhcp '0'
	option leasefile '/tmp/hosts/odhcpd'
	option leasetrigger '/usr/sbin/odhcpd-update'
	option loglevel '4'

config host
	option name 'my-wired-desktop'
	option ip '192.168.0.100'
	option mac 'AB:CD:EF:GH:IJ:KL'

config domain
	option name 'example.com'
	option ip '192.168.0.100'

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

config defaults
	option syn_flood '1'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'

config zone
	option name 'lan'
	list network 'lan'
	option input 'ACCEPT'
	option output 'ACCEPT'
	option forward 'ACCEPT'

config zone
	option name 'wan'
	list network 'wan'
	list network 'wan6'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'
	option masq '1'
	option mtu_fix '1'

config forwarding
	option src 'lan'
	option dest 'wan'

config rule
	option name 'Allow-DHCP-Renew'
	option src 'wan'
	option proto 'udp'
	option dest_port '68'
	option target 'ACCEPT'
	option family 'ipv4'

config rule
	option name 'Allow-Ping'
	option src 'wan'
	option proto 'icmp'
	option icmp_type 'echo-request'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-IGMP'
	option src 'wan'
	option proto 'igmp'
	option family 'ipv4'
	option target 'ACCEPT'

config rule
	option name 'Allow-DHCPv6'
	option src 'wan'
	option proto 'udp'
	option dest_port '546'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-MLD'
	option src 'wan'
	option proto 'icmp'
	option src_ip 'fe80::/10'
	list icmp_type '130/0'
	list icmp_type '131/0'
	list icmp_type '132/0'
	list icmp_type '143/0'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Input'
	option src 'wan'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	list icmp_type 'router-solicitation'
	list icmp_type 'neighbour-solicitation'
	list icmp_type 'router-advertisement'
	list icmp_type 'neighbour-advertisement'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-ICMPv6-Forward'
	option src 'wan'
	option dest '*'
	option proto 'icmp'
	list icmp_type 'echo-request'
	list icmp_type 'echo-reply'
	list icmp_type 'destination-unreachable'
	list icmp_type 'packet-too-big'
	list icmp_type 'time-exceeded'
	list icmp_type 'bad-header'
	list icmp_type 'unknown-header-type'
	option limit '1000/sec'
	option family 'ipv6'
	option target 'ACCEPT'

config rule
	option name 'Allow-IPSec-ESP'
	option src 'wan'
	option dest 'lan'
	option proto 'esp'
	option target 'ACCEPT'

config rule
	option name 'Allow-ISAKMP'
	option src 'wan'
	option dest 'lan'
	option dest_port '500'
	option proto 'udp'
	option target 'ACCEPT'

config redirect
	option dest 'lan'
	option target 'DNAT'
	option name 'Force DNS'
	option src 'lan'
	option src_dport '53'

On the web UI I can see the port lan4 is connected.

The desktop that is not connected has a static lease:

	option name 'my-wired-desktop'
	option ip '192.168.0.100'
	option mac 'AB:CD:EF:GH:IJ:KL'

IIRC, I have tried with and without the static lease.

The domain config is set up for an unrelated issue where I have a DNS entry on cloudflare that points example.com to 192.168.0.100 but this DNS does not resolve through this openwrt router for some reason (resolves on online ns lookup services and using mobile data). Perhaps I have set up my quad9 DNS resolver incorrectly, but that is an unrelated issue that is bypassed using the config domain entry. I have also tried removing this entry but it does not resolve my DHCP issue.

Sorry for the late reply, I had to revert to openwrt 23.05 because I didn't have the time to figure out this issue. I have now re-updated to 24.10 get these details.