Recently seeing DHCP problems

montgomeryb · June 17, 2020, 4:06am

I have been using openwrt on this router for several months (6+) without issue - until recently.

I have a Netgear R6230 and I am running OpenWrt 19.07.3. About a week ago we noticed some devices were not getting addresses. This was on both WiFi and ethernet. Most of the devices are assigned static addresses and these weren't. After adding DHCP to the log file I did see an error no address available. I thought this strange and dropped the lease time and increased the pool of addresses. It seemed to fix the problem but it has reappeared.

Just trying to get an ip address for my phone - it failed and I saw this in the log file:

Tue Jun 16 23:40:13 2020 daemon.warn dnsmasq-dhcp[8725]: not using configured address 10.192.168.84 because it was previously declined
Tue Jun 16 23:40:13 2020 daemon.info dnsmasq-dhcp[8725]: DHCPDISCOVER(br-lan) b8:27:eb:97:4d:05 no address available

The router shows about 25 active ip4 addresses, and about 8 ip6 addresses. The pool for dhcp is about 180 and doesn't include any of the 25. It shows 4% for active connections 760/16384. Memory is at 54%. On the route status page, it does show a whole load more ARP connections. I do notice that one mac address (B8:27:EB:97:4D:05) shows up many different times with different IP addresses. I see that this is a raspberry pi running xbian.

At this point I now plan on powering down the raspberry and rebooting the router.

Is there something else I should look at on OpenWrt, is there something I can do to prevent this from happening? Thanks.

eduperez · June 17, 2020, 5:41am

Please, share you current DHCP config here.

montgomeryb · June 17, 2020, 1:55pm

Thanks, here is dhcp.conf - not sure if there is anything else that would help:

root@OpenWrt:/etc/config# cat dhcp

config dnsmasq
        option domainneeded '1'
        option localise_queries '1'
        option rebind_protection '1'
        option rebind_localhost '1'
        option expandhosts '1'
        option authoritative '1'
        option readethers '1'
        option leasefile '/tmp/dhcp.leases'
        option localservice '1'
        option local '/feeney/'
        option domain 'feeney'
        option logqueries '1'

config dhcp 'lan'
        option interface 'lan'
        option dhcpv6 'server'
        option ra 'server'
        option ra_management '1'
        option start '101'
        option leasetime '6h'
        option limit '85'

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 'printer'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.90'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.23'

config host
        option name 'Tivo-DT'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.22'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.11'
        option name 'ata'
        option dns '1'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.20'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.86'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.88'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.199'
        option name 'slug'
        option dns '1'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.13'
        option name 'thermostat'
        option dns '1'

config host
        option name 'desktop'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.100'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.53'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.55'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.61'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.12'
        option name 'smart-things'
        option dns '1'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.24'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.67'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.80'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.65'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.16'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.25'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.17'

config host
        option name 'ads-b'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.195'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.196'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.191'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option name 'aquanta'
        option dns '1'
        option ip '10.192.168.10'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.26'

config host
        option name 'munitrac'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.198'

config host
        option name 'arlo'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.15'

config host
        option name 'xbian'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.84'

config host
        option name 'wake'
        option dns '1'
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.14'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.69'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.63'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.51'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.60'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.229'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option name 'kodi-pi4'
        option dns '1'
        option ip '10.192.168.89'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.31'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.33'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.35'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.18'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.190'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.196.168.62'

config host
        option mac 'XX:XX:XX:XX:XX:XX'
        option ip '10.192.168.41'

root@OpenWrt:/etc/config#

vuhuy · June 17, 2020, 2:18pm

Looks more like a problem on your RPi running Xbian. You have assigned a IP reservation and that IP address is declined by your RPi. Your RPi is probably declining it because the address is reported to be already in use your ARP table.

Clear the leases on both devices and reboot them (so for both dnsmasq dhcp server and the dhcp client). If that doesn't work, reinstall or try to figure out whats wrong with xbian. Alternatively, set a static IP address on your RPi outside the DHCP range instead of doing a IP reservation on your router.

montgomeryb · June 17, 2020, 2:37pm

Thanks for the suggestion. It wasn't until I wrote the post that I saw the pi was having issues. I've turned it off for now. My phone was able to get it's ip address this morning, we'll see if the other devices that were having issues are all Ok now.

If all's well I can look at the pi and certainly easy enough to set a static address outside of the dhcp pool. I'm not sure if it recently updated - or how old the code is, just strange that I've had that on for months if not years and it just went loopy the past couple of weeks