Control-Z the Sleep Signal

Martin McCormick martin at
Wed Jun 10 21:33:32 UTC 2009

Mel Flynn writes:
> If this is the sole purpose of the program, I would retire it if you're 
> using
> ISC provided software for these services. rndc and omshell can do all of 
> this
> using atomic operations. Information is gathered first, then sent in one 
> block
> to the server, so even if two people try to modify/delete the same 
> record, the
> one that comes first makes the change, and the second one is handled 
> according
> to the new information.

	Quite true. The ISC software is wonderful but it doesn't
deal with static bootP and even worse static IP addresses that
have no bootP associated with them. We have tons of both.
Dynamic DHCP isn't really a good solution for printers and
servers. BootP is much more stable for them since nobody can
bump them off. We have some departments on campus that are like
herding cats in that there is always somebody hard-coding their
IP address in to a DHCP  lease, etc. We have other areas where
people have had the same dynamic lease for literally years and
think it is static.

	We usually set up a subnet about half dynamic and half
static which works well for us. The program I wrote reads the
dhcpd.conf file and blocks out the dynamic ranges so one can not
assign a static entry in those ranges so it has grown to work
with the ISC products.

	It reads the subnet mask, finds the dynamic ranges and
then compares against the A records in DNS to quickly find the
next free IP address.

	We use both bind and the ISC DHCP server and are very
satisfied customers. When you use omshell to add a bootP entry,
it inserts it as a clause in the dhcpd.leases file but you still
must specify all the parameters yourself.

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