On 15/10/15 12:39, Ed W wrote: > Hi, I'm not quite clear from the manual pages, so can I please get a > definitive answer: > > - Am I safe to use to assign a static IP allocation using --dhcp-host > options, *within* an IP range allocated using --dhcp-range ? > > Specifically, whilst I realise that dnsmasq will first ping to see if an > IP is unused: > - Will there be a hard mask on the IP being handed out dynamically as a > result of the --dhcp-host option? > - ie if the static allocated device is missing from the network for some > long period of time, am I "safe" from having a dynamic device "pinch" my > static IP?
Yes. Addresses withing the dynamic range which appear as static allocations are protected from being handed out to other clients. > > Corner case: > - What happens if there is currently a lease allocated to IP w.x.y.z, > and I setup a static --dhcp-host allocation for that IP and a > *different* mac, ie this lease needs to be booted off. Assuming the > lease is technically not expired, and I disconnect the (now errant) > device from the network and reconnect it, will it be able to regain it's > (technically still not expired) lease, or will dnsmasq observe the > static allocation, expire the lease and allocate a new dynamic allocation? For the duration of the existing lease, the existing owner will get to keep it. If the address is set as static for a MAC and that MAC asks for a lease, it will be offered a different address, and a message logged about why. Once the lease expires, the existing owner will not be able to renew the lease, and will move address. Once that's happened, the static-MAC will also not be able to renew its lease, and will move address to the originally allocated static address. > > > Background: > - I do realise it's best practice to have a separate static range > outside of the dynamic allocation range > - For various technical reasons this environment would be massively > simpler if it were possible to safely allocate static allocations > *inside* the dynamic range and have them protected and always available > (ie even if the machine is offline for a long period) > > exec-summary. If you have static allocations in the dynamic range, all will be fine. If you add a new allocation in the dynamic range for an unused address, all will be fine. If you add a new allocation for an address that's already in use, all will eventually be fine, but clients will be move addresses to make it so. Cheers, Simon. Cheers, Simon. _______________________________________________ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
