TP-Link Archer C2 v1 on 23.05 - No internet coming through 5Ghz Wifi + slow 2.4 Ghz

4Style · February 28, 2024, 8:42pm

Hi everyone,
I have a tough time upgrading my old TP-Link Archer C2 v1 from 22.03 to 23.05.2.
The router is configured to be a static IP client for wired connections (so no DHCP server) and an access point for Wi-Fi.

First, for some reason after the update, my PC still had internet connection, but the Wi-Fi was down.
I couldn't access the router via web or ssh, even a simple ping wasn't possible, even though my main router was listing it in the connection list.
I had to put it into failsafe mode and perform a full reset to factory defaults until it was reachable again.

After this was resolved, I discovered that using the 5Ghz Wi-Fi, I don't get any internet traffic through and can't ping external IP addresses.
The clients get correct IP addresses/ gateway etc. but no traffic was possible.
Also, the Wi-Fi disconnects quite regularly.
It doesn't matter if I use WPA 2 or 3 for encryption.

Using 2.4 Ghz Wi-Fi, the traffic is working at least, but it is really slow.
Only about 16 Mbit/s are possible.
For both radios, I have configured the correct country code.

Do you have any ideas what is going wrong here?
I see a few errors in the system and kernel log, but don't know if they are relevant or helpful.
https://pastebin.com/KzDkRip2 (System Log)
https://pastebin.com/QDkxAsSM (Kernel Log)

4Style · March 10, 2024, 4:51pm

Excuse me for the bump, I just want to know if I should put any more hope into this old device or if the time is finally over?

psherman · March 10, 2024, 4:51pm

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

Exio0 · March 10, 2024, 5:17pm

Maybe hardware limitations?

can you use htop (ssh) while using the router could give us a taste

4Style · March 10, 2024, 6:18pm

Here you go:
That's what htop shows when streaming a 1440p video over 2.4 Ghz Wifi:

Load goes often up to 100% and the Luci interface becomes very slow.

4Style · March 10, 2024, 6:23pm

Sure here you go:
ubus call system board


{
	"kernel": "5.15.137",
	"hostname": "OpenWrt",
	"system": "MediaTek MT7620A ver:2 eco:6",
	"model": "TP-Link Archer C2 v1",
	"board_name": "tplink,archer-c2-v1",
	"rootfs_type": "squashfs",
	"release": {
		"distribution": "OpenWrt",
		"version": "23.05.2",
		"revision": "r23630-842932a63d",
		"target": "ramips/mt7620",
		"description": "OpenWrt 23.05.2 r23630-842932a63d"
	}
}

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 'fd87:c4b3:8440::/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 '10.26.3.2'
	option netmask '255.255.255.0'
	option ip6assign '60'
	option gateway '10.26.3.1'
	list dns '10.26.3.1'
	list dns '1.1.1.1'
	list dns '8.8.8.8'

config device
	option name 'eth0.2'
	option macaddr 'a4:2b:b0:df:6e:0a'

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 '1 2 3 4 6t'

config switch_vlan
	option device 'switch1'
	option vlan '2'
	option ports '0 6t'

cat /etc/config/wireless

config wifi-device 'radio0'
	option type 'mac80211'
	option path 'pci0000:00/0000:00:00.0/0000:01:00.0'
	option channel '36'
	option band '5g'
	option htmode 'VHT80'
	option cell_density '0'
	option country 'DE'
	option disabled '1'

config wifi-device 'radio1'
	option type 'mac80211'
	option path 'platform/10180000.wmac'
	option channel 'auto'
	option band '2g'
	option htmode 'HT20'
	option cell_density '0'
	option country 'DE'

config wifi-iface 'wifinet0'
	option device 'radio1'
	option mode 'ap'
	option network 'lan'
	option ssid 'xxx'
	option encryption 'sae-mixed'
	option key 'xxx'

config wifi-iface 'wifinet1'
	option device 'radio0'
	option mode 'ap'
	option ssid 'xxx'
	option encryption 'psk2'
	option key 'xxx'
	option network 'lan'
	option disabled '1'

cat /etc/config/dhcp

config dnsmasq
	option domainneeded '1'
	option boguspriv '1'
	option filterwin2k '0'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option local '/lan/'
	option domain 'lan'
	option expandhosts '1'
	option nonegcache '0'
	option cachesize '1000'
	option authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
	option nonwildcard '1'
	option localservice '1'
	option ednspacket_max '1232'
	option filter_aaaa '0'
	option filter_a '0'

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'
	option ignore '1'

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'

cat /etc/config/firewall



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

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

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

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'

psherman · March 10, 2024, 6:28pm

So this is a dumb AP, right? Is the upstream connection made via lan-lan, or lan-wan?

4Style:

config wifi-device 'radio0'
	option type 'mac80211'
	option path 'pci0000:00/0000:00:00.0/0000:01:00.0'
	option channel '36'
	option band '5g'
	option htmode 'VHT80'
	option cell_density '0'
	option country 'DE'
	option disabled '1'

Your 5G radio is disabled.

4Style:

config wifi-device 'radio1'
	option type 'mac80211'
	option path 'platform/10180000.wmac'
	option channel 'auto'
	option band '2g'
	option htmode 'HT20'
	option cell_density '0'
	option country 'DE'

20MHz channel width on 2.4G is generally going to be slow... what speeds are you getting?

If you connect a computer to one of the lan ports on your C2, does does it get internet connectivity and if so, what are the speeds? Are they in-line with expectations?

Exio0 · March 10, 2024, 6:35pm

I had problems with an Archer C6 connected with PPPoE, still having problems in fact and that was the problem, the board is not able to manage "that speed" (500mbps)

4Style · March 10, 2024, 7:30pm

Yeah it's a dumb AP/switch.
I'm not sure if that's what you asking for but the wireless interface is attached to the Lan interface.
I disabled the 5Ghz radio on purpose because of the connectivity issues that I described above.

And yes I don't expect the 20 MHz Band to be super fast, but 9 MBit up and down are way too slow.
If I connect my laptop via ethernet, I get 250 MBit down and 50 down, which is the maximum speed of our internet connection.

@Exio0
I think in general the board should be fast enough to handle 250mbit (and hopefully a bit more), but there seems to be some issue with the traffic over Wifi.

Exio0 · March 10, 2024, 7:33pm

I really dont know but, C6 is supposed to be better than C2, so...
I just reach 140/150 mbps with C6.

psherman · March 10, 2024, 7:40pm

To clarify -- are you connecting your laptop to the C2 directly?

psherman · March 10, 2024, 7:41pm

Also, I don't think you answered this... how is it connected?

4Style · March 10, 2024, 7:51pm

Yes I plug my laptop directly into the C2 and connect it directly via Wifi.
And yeah sorry, the upstream router is connected via ethernet cable into one of the LAN ports.

The router is connected to LAN port 4.

psherman · March 10, 2024, 7:55pm

I don't see anything that would make the 5GHz behave differently in terms of connectivity compared to the ethernet and 2.4G connections.

That said, it's possible its an IPv6 issue caused by the DHCP server...

4Style:

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'
	option ignore '1'

Remove the lines that have ra and dhcpv6 from the DHCP server.

I also recommend against using sae-mixed. Select either WPA2 or WPA3 -- mixed mode tends to cause problems for many devices.

Reboot after you've changed those things.

4Style · March 12, 2024, 12:51pm

All right, my dhcp config now looks like this:

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option ignore '1'

And I also changed the encryption method to WPA2 only:

config wifi-iface 'wifinet0'
        option device 'radio1'
        option mode 'ap'
        option network 'lan'
        option ssid 'xxx'
        option encryption 'psk2'
        option key 'xxx'

Since I'm not at home right now, I can't test if this improved the performance, but I will report when I'm back.

4Style · March 24, 2024, 4:14pm

All right, this is resolved now.
Thanks for your hints about the DHCPv6 config, now my 5 Ghz Wifi is working again and i get around 200 Mbit/s of throughput.
I wonder why this is not the default value?

Also using pure WPA2 (with no MFP) instead of WPA 3 made a huge difference, because as enmaskarado pointed out in this GitHub issue, the processor has no hardware accelleration for MFP (whatever this is) and software emulation limits the speed to around 18 Mbit/s, which is exactly what i noticed.
With WPA2 enabled again, i get around 45 Mbit/s throughput using 2.4 Ghz Wi-Fi (20 mhz channel).

This also explains why the router was lagging so much as soon as I started using it a bit more heavily.

system · April 3, 2024, 4:17pm

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