Eric Spakman wrote:

>Hello Joep,
>  
>
>No, that's not cheating but exactly how it's supposed to be ;)
>
>The "_dynamic_ host configuration protocol" (dhcp) is a protocol that
>assigns an ip-address and other values to an host and also stores some
>info about that host in a lease file (dnsmasq.leases). The lease file
>contains information about how long a lease is valid, etc.
>
>What you are doing is basicly bypassing dhcp and _statically_ configure
>the host. The dhcp daemon has no knowledge about those static hosts (they
>don't ask for a lease) and so they are not stored in a leases file (and
>they shouldn't).
>
>You have a few options to let dnsmasq (the caching dns part) know about
>those hosts:
>-Use the /etc/hosts file, this is a very simple "dns" implementation.
>Dnsmasq will read this file and knows the names and ip-addresses.
>-Always give certain hosts a "fixed" dhcp address (something like below,
>but there a a lot of exemples in the dnsmasq.conf file)
>dhcp-host=joep,192.168.1.20,infinite
>-Use something like tinydns on the router (a dns server).
>
>  
>
>Correct, the leases file is not persistant. If you reboot your system the
>file is lost and the client info will be "added" again after the clients
>reach half of there lease time and report back to dnsmasq's dhcp daemon.
>Note that dhcp is a client driven process, the clients asks the daemon for
>a lease not vice versa.
>
>Dnsmasq doesn't do a broadcast for two obvious reasons:
>-It's not in the RFC
>-It doesn't work reliable, because a broadcast will not pass subnets. So
>if you have an other router in the path (with a relay daemon) a broadcast
>from the dnsmasq dhcpd will not pass that router and reach the clients. It
>would be a very bad idea also, because the whole idea of subnetting is to
>limit the broadcast domain :)
>  
>
>Eric
>
>
>
>  
>
Eric,
Thanks very much for your elaborate and lucid answer. Especially your 
explanation regarding the lease time was unknown to me. There should be 
however, some method to let the clients know that the dhcp server is up 
again and let them automatically renew their lease. I now do it manually 
for the few systems I manage in my own net but if you manage a network 
with a few hundred systems it can be a nuisance. The only thing I can 
think of is to use short lease times (e.g. 1 hour or less) but this will 
generate more traffic. But maybe that is a solution.
Regarding my first question I don't think it very difficult to 
automatically store the static addresses and their names in the .leases 
file when starting dnsmasq but maybe there are other reasons why this 
isn't done.
Joep


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