Loading dhcpd.conf changes without restarting the dhcpd daemon

Simon Hobson dhcp1 at thehobsons.co.uk
Thu Mar 14 13:38:57 UTC 2013

Abdul Khader wrote:
>I would like to know if there is any hack which will allow dhcpd.conf
>changes to be loaded without actually stopping and restarting the
>dhcpd ?

I'm fairly certain there isn't, however restarting is normally very quick (unless you have some huge and/or very complicated setup).

In practical terms, there are two ways to do a reload.
The simplest is to simply flush all existing data and just to the program's initial entry point - ie do pretty well the same thing as quit-and-restart.
The second is to write a lot of code to alter in-memory tables on the fly. This is a lot of work, and (IMO quite correctly) ISC took the attitude that since the first option is normally quite quick enough to be practical, the extra work of designing, writing, debuggingh, and maintaining code that is only really needed by a tiny minority of users wasn't a good invetment.

So the obvious question has to be, what is it you are doing that makes a stop-start undesirable ? It may be that there are way around any issues you are seeing.

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