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From: The Natural Philosopher <tnp@invalid.invalid>
Newsgroups: comp.os.linux.misc
Subject: Re: I never thought of this scenario
Date: Mon, 8 Apr 2024 09:19:24 +0100
Organization: A little, after lunch
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On 08/04/2024 08:35, The Natural Philosopher wrote:
> On 08/04/2024 00:53, Lawrence D'Oliveiro wrote:
>> On Sun, 7 Apr 2024 13:24:28 +0100, The Natural Philosopher wrote:
>>
>>> On 07/04/2024 12:37, Robert Heller wrote:
>>>>
>>>> I believe that the DHCP server process does
>>>> something like an "arp" before it assigns leaases.
>>>
>>> I think it may in fact do a *ping*.
>>
>> You want it to do an ARP, not a ping. Ping is routable, ARP is not.
> What I want to do is not in question, What is (apparently) generally 
> accepted practice, is.

I found this, which seems relatively authoritative.

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

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



-- 
No Apple devices were knowingly used in the preparation of this post.