newbies questions

Simon Hobson dhcp1 at thehobsons.co.uk
Fri Oct 18 15:43:45 UTC 2013


"Pol Hallen" wrote:
>1) when is necessary clear the file dhcpd.leases? (/var/lib/dhcp/)

Rarely, if ever. Most users will never need to clear this file, and it is something you should not do without good reason. This file contains data on every "promise" made by the server to clients - if you clear it, then the server doesn't know what addresses it has given out and you are likely to get conflicts.

>2) with a dhcp range (i.e.) 192.168.1.1 - 192.168.1.20, dhcp server does
>an echo request for known if IP is available. If I've (with static IP) a
>machine with IP 192.168.1.5 and iptables blocks echo requests, should I've
>an IP conflicts?


Yes, you will get a conflict. It is your job as network administrator to configure the network properly and manage it. If you know there is a device on that IP address, then you should exclude that address from all pools. Ie you should never ever have an address shich is both dynamically assigned (by being in a pool) and configured by other means.

>3) last question :-) after dhcp assigns me an IP, if I change that IP and
>put same IP of gateway I can crack whole network? How disallow this
>situation?

DHCP can't help you with this, see the reply fromOskar Berggren


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