Internet keeps stopping in Xiaomi 4a(gigabit edi) router with openwrt

I have a GPON ONT modem router as my primary router.
This device is shared between multiple people,
some of those people keeps sharing wifi password wifi QR code
So,
I purchased Xiaomi 4A and flash with openwrt and applied mac filter to all(60) (my GPON don't support more than 16 mac filter and also openwrt not supported for that).

It was working for sometime but then Internet keeps stopping in openwrt router.
restart solves the issue but it keeps happening

openwrt router is connected via LAN cable to GPON router
openwrt ip range -> 10.20.30.40 (I change to this bcz I thought maybe both having same ip range was causing the issue)
GPON ip range -> 192.168.1.1
also both router is running its own DHCP server
also both router is in same room
I wonder if running openwrt router in Bridge mode will solve the issue?

If the limit on the ISP's ONT/router is purely about the number of devices that can connect via wifi, you could set your OpenWrt router up as a dumb AP:

If, however, the limit is on the number of devices in general (wired or wireless) that can connect to the ONT/router device, a dumb AP (bridge device) won't help.

We cannot say at this point why your internet connection is stopping -- it could be related to the upstream ONT/router (i.e. too many devices connected), or it could be due to a misconfiguration of your router... to rule in/out the latter, let's look at your configuration:

c

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:
grafik
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

ubus call system board -

{
        "kernel": "5.15.137",
        "hostname": "OpenWrt",
        "system": "MediaTek MT7621 ver:1 eco:3",
        "model": "Xiaomi Mi Router 4A Gigabit Edition",
        "board_name": "xiaomi,mi-router-4a-gigabit",
        "rootfs_type": "squashfs",
        "release": {
                "distribution": "OpenWrt",
                "version": "23.05.2",
                "revision": "r23630-842932a63d",
                "target": "ramips/mt7621",
                "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 'fdc9:f6fb:58a0::/48'
        option packet_steering '1'

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

config interface 'lan'
        option device 'br-lan'
        option proto 'static'
        option ipaddr '10.20.30.40'
        option netmask '255.255.255.0'
        option ip6assign '60'
        list dns '1.0.0.1'
        list dns '1.1.1.1'

config interface 'wan'
        option device 'wan'
        option proto 'dhcp'
        option peerdns '0'
        list dns '1.0.0.1'
        list dns '1.1.1.1'

config interface 'wan6'
        option device 'wan'
        option proto 'dhcpv6'
        option reqaddress 'try'
        option reqprefix 'auto'
        option peerdns '0'
        list dns '1.0.0.1'
        list dns '1.1.1.1'

cat /etc/config/wireless -

config wifi-device 'radio0'
        option type 'mac80211'
        option path '1e140000.pcie/pci0000:00/0000:00:01.0/0000:02:00.0'
        option channel '1'
        option band '2g'
        option htmode 'HT20'
        option cell_density '0'

config wifi-iface 'default_radio0'
        option device 'radio0'
        option network 'lan'
        option mode 'ap'
        option ssid 'TESTwifi'
        option encryption 'none'
        option key 'password'
        option macfilter 'allow'
        list maclist 'XX:XX:XX:XX:XX:XX'
	--n no. of maclist--

config wifi-device 'radio1'
        option type 'mac80211'
        option path '1e140000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0'
        option channel '36'
        option band '5g'
        option htmode 'VHT80'
        option cell_density '0'

config wifi-iface 'default_radio1'
        option device 'radio1'
        option network 'lan'
        option mode 'ap'
        option ssid 'TESTwifi'
        option encryption 'none'
        option key 'password'
        option macfilter 'allow'
        list maclist 'XX:XX:XX:XX:XX:XX'
	--n no. of maclist--

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'

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
# Uncomment this line to disable ipv6 rules
#       option disable_ipv6     1

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

# We need to accept udp packets on port 68,
# see https://dev.openwrt.org/ticket/4108
config rule
        option name             Allow-DHCP-Renew
        option src              wan
        option proto            udp
        option dest_port        68
        option target           ACCEPT
        option family           ipv4

# Allow IPv4 ping
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

# Allow DHCPv6 replies
# see https://github.com/openwrt/openwrt/issues/5066
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

# Allow essential incoming IPv6 ICMP traffic
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

# Allow essential forwarded IPv6 ICMP traffic
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


### EXAMPLE CONFIG SECTIONS
# do not allow a specific ip to access wan
#config rule
#       option src              lan
#       option src_ip   192.168.45.2
#       option dest             wan
#       option proto    tcp
#       option target   REJECT

# block a specific mac on wan
#config rule
#       option dest             wan
#       option src_mac  00:11:22:33:44:66
#       option target   REJECT

# block incoming ICMP traffic on a zone
#config rule
#       option src              lan
#       option proto    ICMP
#       option target   DROP

# port redirect port coming in on wan to lan
#config redirect
#       option src                      wan
#       option src_dport        80
#       option dest                     lan
#       option dest_ip          192.168.16.235
#       option dest_port        80
#       option proto            tcp

# port redirect of remapped ssh port (22001) on wan
#config redirect
#       option src              wan
#       option src_dport        22001
#       option dest             lan
#       option dest_port        22
#       option proto            tcp

### FULL CONFIG SECTIONS
#config rule
#       option src              lan
#       option src_ip   192.168.45.2
#       option src_mac  00:11:22:33:44:55
#       option src_port 80
#       option dest             wan
#       option dest_ip  194.25.2.129
#       option dest_port        120
#       option proto    tcp
#       option target   REJECT

#config redirect
#       option src              lan
#       option src_ip   192.168.45.2
#       option src_mac  00:11:22:33:44:55
#       option src_port         1024
#       option src_dport        80
#       option dest_ip  194.25.2.129
#       option dest_port        120
#       option proto    tcp

Hi. I think i had same problem as you, i.e. my brother. He has 3 Xiaomi 4A GE in Mesh and the Mesh gateway is connected to ISP router and sends 2,4GHz WLAN. Mesh is on 5GHz. After updating from 22.03.6 to 23.05.02 (same as your version) he expirienced some issue (Inaccessable LUCI, very slow SSH and of course no internet connection). Those issues would suggest there is some OOM problems with 23.05.2 version.
We upgraded all 3 routers to snapshot from 21-03-2024 and there were no OOM issues anymore, but some other issues that make some nodes of the mesh inaccessable (There is some other problem, i have to investigate).
You can try 22.03 series and i am sure it will work really great. I have only good expirience with this model. We had 90+ uptime days with those releases.
We upgraded now to 23.05.3 and we will see if it is any better. I hope someone from dev is going to see this. I have one 4AGE running on 23.05.2 on my own mesh and waiting for it to crash, then i can post some dmesg messages and more details.

Best regards