ARP and DHCP not working in lan

[CedricH]

Hey everyone,

I've been using my router with OpenWRT for about 3 years now and for most of that time it has been working flawlessly. However, about 6 months ago the wan port on my router stopped working. I'm not quite sure why but I suspect it's a hardware problem. Since the router has 4 other ports and I was only using 2 of them anyway, I thought I'd just configure it to use one of the other ports as the wan port. That worked, mostly, but ever since I've been experiencing some wired behavior:

1. The router doesn't reply to ARP packages anymore. I can see with wireshark, that my PC's are sending ARP requests, but the router doesn't send any responses. I can work around this by either logging into the router with another device and manually sending an ARP response, using arping, or adding the router manually to my ARP table.
2. The router doesn't give out IP addresses. I can get around this by setting static IP addresses.
3. Possibly because of the first two issues, I can't see certain devices on my network at all. Like my RaspberryPi's or my Philips Hue bridge.

My config looks like this:

network:

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 'fd86:4629:7761::/48'

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

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

config switch_vlan
	option device 'switch0'
	option vlan '1'
	option vid '1'
	option ports '0t 2 3 4'

config switch_vlan
	option device 'switch0'
	option vlan '2'
	option ports '0t 1t'
	option vid '7'

config interface 'wan'
	option proto 'pppoe'
	option ifname 'eth0.7'
	option username '**********'
	option password '**********'
	option ipv6 'auto'

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 authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option resolvfile '/tmp/resolv.conf.auto'
	option nonwildcard '1'
	option localservice '1'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv6 'server'
	option ra 'server'
	option ra_management '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'

config host
	option name 'My-Desktop-PC'
	option dns '1'
	option mac '**:**:**:**:**:**'
	option ip '192.168.1.101'
	option leasetime '9999999999999999999999999'

firewall:

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

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

config zone
	option name 'wan'
	option input 'REJECT'
	option output 'ACCEPT'
	option forward 'REJECT'
	option masq '1'
	option mtu_fix '1'
	option network 'wan wan6 WAN_2'

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 src_ip 'fc00::/6'
	option dest_ip 'fc00::/6'
	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 include
	option path '/etc/firewall.user'

wireless:

config wifi-device 'radio0'
	option type 'mac80211'
	option channel '11'
	option hwmode '11g'
	option path 'platform/qca953x_wmac'
	option htmode 'HT20'
	option disabled '0'
	option country 'US'
	option legacy_rates '1'

config wifi-iface 'default_radio0'
	option device 'radio0'
	option mode 'ap'
	option ssid 'SomeSSID'
	option encryption 'psk2'
	option key '************'
	option network 'lan'

Let me know if further information is required.

The vlan tagging in the network config is necessary for my ISP, see here

Thanks for taking the time to read this. I hope someone can help me figure this out.

[psherman]

Try removing eth0 from your lan interface (keep eth0.1).

Also remove the lease time parameter from your dhcp file for your pc.

[CedricH]

Thanks, removing eth0 seems to have done the trick. I just removed the whole static entry for my PC from the DHCP file, as automatic DHCP seems to work again.
Other devices connect automatically again and I can reach my Hue bridge. Still having problems with one of my Pi's but I think that might be a problem on the Pi's end.