[Dnsmasq-discuss] static lease issues?

[Simon Kelley]

On 05/11/2018 03:30, Kevin Darbyshire-Bryant wrote:
> Hi Simon, Hi List,
> 
> I’m hearing rumblings from the openwrt community that something isn’t right with static leases.   The behaviour manifests itself as the statically assigned host being unable to renew its lease.  e.g.
> 
> -this is okay
> Nov  4 15:29:29 192.168.0.254 dnsmasq-dhcp[2378]: 424644159 available DHCP range: 192.168.0.100 -- 192.168.0.199
> Nov  4 15:29:29 192.168.0.254 dnsmasq-dhcp[2378]: 424644159 client provides name: sylvester
> Nov  4 15:29:29 192.168.0.254 dnsmasq-dhcp[2378]: 424644159 DHCPDISCOVER(eth0.54) 00:11:22:33:44:55
> Nov  4 15:29:29 192.168.0.254 dnsmasq-dhcp[2378]: 424644159 tags: lan, known, eth0.54

> Nov  4 15:29:29 192.168.0.254 dnsmasq-dhcp[2378]: 424644159 DHCPOFFER(eth0.54) 192.168.0.12 00:11:22:33:44:55
> -but later
> 
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 available DHCP range: 192.168.0.100 -- 192.168.0.199
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 client provides name: sylvester
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 DHCPREQUEST(eth0.54) 192.168.0.12 00:11:22:33:44:55
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 DHCPNAK(eth0.54) 192.168.0.12 00:11:22:33:44:55 address not available
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 broadcast response
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 sent size:  1 option: 53 message-type  6
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 sent size:  4 option: 54 server-identifier  192.168.0.254
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 53015875 sent size: 21 option: 56 message  61:64:64:72:65:73:73:20:6e:6f:74:20:61:76...
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 1321333264 available DHCP range: 192.168.0.100 -- 192.168.0.199
> Nov  4 15:52:32 192.168.0.254 dnsmasq-dhcp[2378]: 1321333264 client provides name: sylvester
> Nov  4 15:52:36 192.168.0.254 dnsmasq-dhcp[2378]: 1321333264 DHCPDISCOVER(eth0.54) 00:11:22:33:44:55
> Nov  4 15:52:36 192.168.0.254 dnsmasq-dhcp[2378]: 1321333264 tags: lan, known-othernet, eth0.54
> Nov  4 15:52:36 192.168.0.254 dnsmasq-dhcp[2378]: 1321333264 DHCPOFFER(eth0.54) 192.168.0.190 00:11:22:33:44:55
> 
> I have yet to see this behaviour personally, so I’m putting this out there as a) anyone else b) any ideas on debugging?
> 
> 


Look at the tags on the first and second DHCPDISCOVERs. The first one is
in "known" and the second is "known-othernet".

"known" means that the host has a dhcp-host or similar configuration
which provides an address, and the address in in scope for the network
it's talking from. "known-othernet" means the same, but the the address
is NOT in scope.

That probably explains the DHCPNAK too.

The question is "what's changed". difficult to tell. Maybe the netmask
on the interface?


Cheers,

Simon.