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From: Grant Taylor <gtaylor@tnetconsulting.net>
Newsgroups: comp.os.linux.misc
Subject: Re: I never thought of this scenario
Date: Mon, 8 Apr 2024 18:30:37 -0500
Organization: TNet Consulting
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On 4/8/24 03:19, The Natural Philosopher wrote:
> "With conflict detection enabled, the DHCP Server will ping the IP 
> address it wants to grant a lease for to make sure no other computers 
> are using that IP address. If the ping request receives a reply, the 
> server will mark the IP as BAD_ADDRESS. If no response is received, the 
> server will assign the IP address to the requesting client...."

This usually works well enough.  But it breaks down when the system 
using the IP the DHCP server is ping testing refuses to send echo reply 
responses to the ping.

> (The DHCP client probes the IP address by sending gratuitous ARP 
> packets)

I wonder if this happens after the client receives the DHCP OFFER from 
the server and before the client sends the DHCP REQUEST (for the offered 
IP).

> Apparently the use of ping is preferred because a DHCP server can 
> operate across various routed subdomains.

That doesn't surprise me.  But it does have limitations in some probably 
rare cases.



-- 
Grant. . . .