DHCP lease DORA

Hi
I have a Scenario with DHCP lease. Want to underetand the "behind the
scenes"
I am looking for a way to renew the IP address of a client. lets assume the
client has a 10.10.10.1 ipaddress. The way DHCP lease process works, the
client will ask for a renewal at 50 % of DHCP lease period.
I am stuck at "behind the scenes".
1) the client sends a UNICAT request to DHCP server for renewal
2) server identifies the client based on ARP entry in the cache.
3) It looks at the DHCP leases and relates the mac-address to the leased out
IP address and thus confirms the client machine
4) Renews the lease.

The DHCP server will have the arp cache and the IPaddres lease table to
" CONFIRM " that it is the right Client machine.
Please correct me if i am wrong.
--
make the change

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make the change


"Poppen" wrote:

> Hi
> I have a Scenario with DHCP lease. Want to underetand the "behind the
> scenes"
> I am looking for a way to renew the IP address of a client. lets assume the
> client has a 10.10.10.1 ipaddress. The way DHCP lease process works, the
> client will ask for a renewal at 50 % of DHCP lease period.
> I am stuck at "behind the scenes".
> 1) the client sends a UNICAT request to DHCP server for renewal
> 2) server identifies the client based on ARP entry in the cache.
> 3) It looks at the DHCP leases and relates the mac-address to the leased out
> IP address and thus confirms the client machine
> 4) Renews the lease.
>
> The DHCP server will have the arp cache and the IPaddres lease table to
> " CONFIRM " that it is the right Client machine.
=============
Having said this much

I need to get a new IP address to the machine.
As long as I DO NOT exclude the original IP address( 10.10.10.1 ) from
DHCP lease the system will get the same IP address from the DHCP.
REASON being the DHCP server maintains the arp entry of the client
(10.10.10.1 ) in its arp cache and the dhcp lease table relates this arp
entry to the specific IP address.(10.10.10.1 )
I am trying to understand the WAY this DHCP lease works because I have
a linux box ( that does the DHCP leases ) that does not let us exclude the IP
address like a windows machine does. Hence we often have to manually assign
the IP addresses that are NOT present in the DHCP lease table of the linux
box if situation desires so.
What I want to know is
what are the tables the DHCP server ( GENERIC to DORA process ) verify
before giving out an address to a machine who already has an IP address
assigned to it.
1) the arp cache on the server
2) the dhcp lease table which has mac to Ip address mapping
....................

Thank YO u