NSlookup fails after adding static lease (sometimes)

I have an intermittent issue with static leases. Sometimes when I add a lease it breaks the Nslookup. Rebooting does not fix it. If I delete the entry and save, it works again. If I then add the same entry again it most often works properly. I get the impression that the problem must be some sort of corruption of the file containing the static lease information, which can be repaired by deleting the last added entry. Has anyone else experienced this ?

OpenWrt 18.06.1 r7258-5eb055306f / LuCI openwrt-18.06 branch (git-18.247.71242-9541751) 4.9.120 xRX200 rev 1.2

Are you adding the entry to /etc/config/dhcp - or elsewhere?

I am using luci.
http://192.168.1.1/cgi-bin/luci/admin/network/dhcp

I have done a bit more work I am finding its the 40 th entry that breaks it.

@jow @hnyman and @dibdot assisted me with an issue where large configs were not saved properly...perhaps this problem is similar.

  • Can you more clearly describe the nslookup issue. Is it that your hostnames in the Static Lease list aren't being resolved?

As an example if I use the diagnostic on
http://192.168.1.1/cgi-bin/luci/admin/network/diagnostics
to test the NSlookup using "openwrt.org" it fails.

It is anything that needs DNS I think.

Do you have a DNS server specified for the WAN Interface?

I am using default settings and it gets the WAN DNS1 & DNS2 from the ISP .

The fault behavior is as if the dnsmasq stops working when the 40 th entry in the static hosts table is reached.

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I found this article on a different system that also uses dnsmasq.

I think this might explain what is happening with dnsmasq on OpenWrt.

You're adding duplicate DHCP entries?

I'm not sure why you believe that link has information related to the issue you're experiencing.

I now realise that the problem is duplicate entries.
If I remove the duplicate entry all is fine.
log attached.

Fri Nov  9 11:29:14 2018 daemon.err odhcp6c[5380]: Failed to send DHCPV6 message to ff02::1:2 (Permission denied)
Fri Nov  9 11:30:28 2018 daemon.info dnsmasq[1760]: exiting on receipt of SIGTERM
Fri Nov  9 11:30:28 2018 daemon.crit dnsmasq[7910]: duplicate dhcp-host IP address 192.168.1.160 at line 58 of /var/etc/dnsmasq.conf.cfg01411c
Fri Nov  9 11:30:28 2018 daemon.crit dnsmasq[7910]: FAILED to start up
Fri Nov  9 11:30:29 2018 user.notice dnsmasq: DNS rebinding protection is active, will discard upstream RFC1918 responses!
Fri Nov  9 11:30:29 2018 user.notice dnsmasq: Allowing 127.0.0.0/8 responses
Fri Nov  9 11:30:31 2018 daemon.crit dnsmasq[7999]: duplicate dhcp-host IP address 192.168.1.160 at line 58 of /var/etc/dnsmasq.conf.cfg01411c
Fri Nov  9 11:30:31 2018 daemon.crit dnsmasq[7999]: FAILED to start up
Fri Nov  9 11:30:36 2018 kern.warn kernel: [88555.463612] br-lan: received packet on eth0.1 with own address as source address
Fri Nov  9 11:30:36 2018 daemon.crit dnsmasq[8180]: duplicate dhcp-host IP address 192.168.1.160 at line 58 of /var/etc/dnsmasq.conf.cfg01411c
Fri Nov  9 11:30:36 2018 daemon.crit dnsmasq[8180]: FAILED to start up
Fri Nov  9 11:30:37 2018 kern.warn kernel: [88556.836151] br-lan: received packet on eth0.1 with own address as source address
Fri Nov  9 11:30:41 2018 daemon.crit dnsmasq[8202]: duplicate dhcp-host IP address 192.168.1.160 at line 58 of /var/etc/dnsmasq.conf.cfg01411c
Fri Nov  9 11:30:41 2018 daemon.crit dnsmasq[8202]: FAILED to start up
Fri Nov  9 11:30:46 2018 daemon.crit dnsmasq[8203]: duplicate dhcp-host IP address 192.168.1.160 at line 58 of /var/etc/dnsmasq.conf.cfg01411c
Fri Nov  9 11:30:46 2018 daemon.crit dnsmasq[8203]: FAILED to start up
Fri Nov  9 11:30:51 2018 daemon.crit dnsmasq[8204]: duplicate dhcp-host IP address 192.168.1.160 at line 58 of /var/etc/dnsmasq.conf.cfg01411c
Fri Nov  9 11:30:51 2018 daemon.crit dnsmasq[8204]: FAILED to start up
Fri Nov  9 11:30:51 2018 daemon.info procd: Instance dnsmasq::cfg01411c s in a crash loop 6 crashes, 0 seconds since last crash
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Glad you got it working. Feel free to mark the thread as solved.

Also, in the future, please use the </> button to enclose your logs and output.

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