New server gets DHCP declined on Linksys 1900ACS Chaos Calmer

Dear forum,

Not sure if this is an OpenWrt issue, something to do with the OpenMediaVault server I am trying to install, or both. OMV was installed to use DHCP. (I have tried to reconfigure it, but it looks like the utility there does not work. The OpenWrt log indicates that DHCP is used regardless of OMV settings.)

I have added the new host to the list of hosts in the "static leases" section under DHCP in LuCi and confirmed the contents of the config file as:

config host
	option name 'Bolivar'
	option dns '1'
	option mac 'AB:CD:EF:31:60:1F'    (not real MAC address)
	option ip '192.168.0.220'

This is what the log file says:

Wed Jun 24 14:03:04 2020 daemon.warn dnsmasq-dhcp[6168]: not using configured address 192.168.0.220 because it was previously declined
Wed Jun 24 14:03:04 2020 daemon.info dnsmasq-dhcp[6168]: DHCPDISCOVER(br-lan) 192.168.0.220 ab:cd:ef:31:60:1f
Wed Jun 24 14:03:04 2020 daemon.info dnsmasq-dhcp[6168]: DHCPOFFER(br-lan) 192.168.0.126 ab:cd:ef:31:60:1f
Wed Jun 24 14:03:04 2020 daemon.info dnsmasq-dhcp[6168]: DHCPREQUEST(br-lan) 192.168.0.126 ab:cd:ef:31:60:1f
Wed Jun 24 14:03:04 2020 daemon.info dnsmasq-dhcp[6168]: DHCPACK(br-lan) 192.168.0.126 ab:cd:ef:31:60:1f Bolivar
Wed Jun 24 14:03:04 2020 daemon.warn dnsmasq-dhcp[6168]: not giving name Bolivar.lan to the DHCP lease of 192.168.0.126 because the name exists in /tmp/hosts/dhcp.cfg01411c with address 192.168.0.220
Wed Jun 24 14:03:04 2020 daemon.info dnsmasq-dhcp[6168]: DHCPDECLINE(br-lan) 192.168.0.126 ab:cd:ef:31:60:1f

The DHCP server is trying one IP address after another and then throws the warning about "not giving name...". I was able to check the IP on the OpenMediaVault server and it displays an address in the DHCP range as "primary" and 192.168.0.220 as "secondary". Neither works. However, I am able to ping anything on the network from it, but not vice versa. I shut the OMV server down (poweroff) overnight to clear the "..previously declined.." stuff, but it got declined instantly as soon as I started it up again.

I have now ran out of ideas of what to do next. Do you have any?

Cheers,
/Chris

Try the following:
Disconnect the OMV from the network

service dnsmasq stop
rm /tmp/hosts/dhcp.cfg01411c
service dnsmasq start

Reconnect the OMV and let it try to acquire settings.

Chaos Calmer is old and unsupported though. We won't be able to replicate troubleshooting. It's advised to upgrade to 19.07.3

Thanks for rushing out to help! =)

Unfortunately, it had no effect. This is the log after the actions you suggested:

Wed Jun 24 15:55:45 2020 daemon.info dnsmasq-dhcp[19874]: DHCPDISCOVER(br-lan) 192.168.0.220 ab:cd:ef:31:60:1f
Wed Jun 24 15:55:45 2020 daemon.info dnsmasq-dhcp[19874]: DHCPOFFER(br-lan) 192.168.0.220 ab:cd:ef:31:60:1f
Wed Jun 24 15:55:45 2020 daemon.info dnsmasq-dhcp[19874]: DHCPREQUEST(br-lan) 192.168.0.220 ab:cd:ef:31:60:1f
Wed Jun 24 15:55:45 2020 daemon.info dnsmasq-dhcp[19874]: DHCPACK(br-lan) 192.168.0.220 ab:cd:ef:31:60:1f Bolivar
Wed Jun 24 15:55:45 2020 daemon.info dnsmasq-dhcp[19874]: DHCPDECLINE(br-lan) 192.168.0.220 ab:cd:ef:31:60:1f
Wed Jun 24 15:55:45 2020 daemon.warn dnsmasq-dhcp[19874]: disabling DHCP static address 192.168.0.220 for 10m
Wed Jun 24 15:55:55 2020 daemon.warn dnsmasq-dhcp[19874]: not using configured address 192.168.0.220 because it was previously declined

I realize that there is no way around upgrading, but that is a separate project. Looks easier these days, though, doesn't it?

The DHCPDECLINE is sent from the client (OMV in your case). This happens if the gratuitous ARP fails, which means that OMV checked if the address is used and found out that it is. In some cases it can be caused by proxy-arp on a firewall, but I don't think this is the case. You can look for yourself with arp if the address is used by some other host.

It's quite straight forward.

"arp" produces a long list of dynamic IP:s consumed by the OMV host as it continuously tries again, but 192.168.0.220 is not in it. If I leave OMV up and running, the DHCP server in OpenWRT runs out of addresses. The OMV dynamic IP is assigned about ten seconds before it retries, so it is quite impossible to ssh there.

If other DHCP clients work properly, I don't see how is this a problem of OpenWrt.
But just to be sure, you can connect the OMV on another router and see if it will acquire successfully the settings.

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Brilliant idea! I am just so sorry I wasn't the one to hatch it... :wink:

True enough. The behavior is exactly the same on another router. That isolates the problem to OMV. Case closed.

Thank you so much trendy for assisting me with this!
=)

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