DHCP server reload on own event

[Robert Wallner]

It's a local prepaid public network of access points. The idea was to
record each mac address connecting to it, and to pair it with an ip
address and the used access point, and generate dynamic iptables rules
from it. The reason behind it is that the website needs to identify
which client connects to it (no mac, only ip), and to make it easy to
detect spoofed mac attempts..

For now, the infinite lease-time answers my problem, but for sure I
got it wrong somewhere else :)


On Tue, Dec 27, 2011 at 11:08 AM, Shachar Shemesh <shachar at shemesh.biz> wrote:
> On 12/27/2011 10:35 AM, Robert Wallner wrote:
>
> I thought about that, but, if the dhcp server looses the leases file
> (/var/lib/dhcp/dhcpd.leases), everything will be out of sync.
> The only authority should be the list in the database.
>
> Then, by all means, generate a static allocation file from the database,
> just don't bother with reloading the server. If the lease file is lost (how,
> exactly?) then that would, within reason, be accompanied by a server
> restart.
>
> As long as your server does not have an uptime of over 28 years, you're
> gold.
>
> Shachar
>
>
> On Tue, Dec 27, 2011 at 10:20 AM, shimi <linux-il at shimi.net> wrote:
>
> On Tue, Dec 27, 2011 at 9:56 AM, Robert Wallner <kodixos at gmail.com> wrote:
>
> In a DHCP server setup, I have 2 requirements:
>
> 1. Each client's mac address must be recorded in a database together
> with the IP address assigned.
> 2. Every new assigned IP address must be given from now on to the same
> mac address only, and to nobody else.
>
> The first one is easy, I use the on-submit event handler to run an
> external program to insert the mac address in the database.
> I have problems with the second one. The same external program scans
> the database, and generates a config file for the DHCP server that is
> included from the main config file, and contains "fixed-address"
> entries for all the mac addresses. The problem is how I make the
> server reload it's configuration files, from it's own "on-submit"
> event handler??
>
> Or am I completely in the wrong direction?
>
>
> Couldn't both requirements be solved[*] by using:
>
> default-lease-time infinite;
> max-lease-time infinite;
> min-lease-time infinite;
>
> in dhcpd.conf ?
>
> -- Shimi
>
> [*] I tried answering myself, and found [1] which claims the lease will hold
> for 914M seconds [per a sniffer]. From some reason he believes that would be
> 14.4 years. My Kcalc said 914M/(86400*365) is actually 28.98 years...
> Wouldn't we have to worry about Bug 2038 first?
>
> [1] https://lists.isc.org/pipermail/dhcp-users/2009-February/008040.html
>
>
>
>
> --
> Shachar Shemesh
> Lingnu Open Source Consulting Ltd.
> http://www.lingnu.com



-- 
Robert Wallner