Re: Spurious ARP entries...

From	The Natural Philosopher <tnp@invalid.invalid>
Newsgroups	comp.os.linux.misc
Subject	Re: Spurious ARP entries...
Date	2025-07-13 11:52 +0100
Organization	A little, after lunch
Message-ID	<105035c$2n9pg$8@dont-email.me> (permalink)
References	<104tdg2$22i42$14@dont-email.me> <9LCdnVkd__WVbO_1nZ2dnZfqn_adnZ2d@giganews.com>

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On 13/07/2025 00:33, c186282 wrote:
> On 7/12/25 6:30 AM, The Natural Philosopher wrote:
>>
>> For unrelated reasons I took a look at my desktop ARP cache just now..
>>
>> $arp -a
>> _gateway (192.168.0.254) at 00:1d:aa:79:78:40 [ether] on eno1
>> pifi2 (192.168.0.202) at 2c:cf:67:88:c9:4b [ether] on eno1
>> ? (192.168.0.248) at <incomplete> on eno1
>> ? (192.168.0.2) at 1c:5a:3e:7e:37:1f [ether] on eno1
>> ? (192.168.0.221) at <incomplete> on eno1
>> ? (192.168.0.223) at <incomplete> on eno1
>> Coriolanus (192.168.0.101) at d8:3a:dd:85:22:b1 [ether] on eno1
>> ? (192.168.0.141) at <incomplete> on eno1
>> ? (192.168.0.10) at <incomplete> on eno1
>> ? (192.168.0.58) at <incomplete> on eno1
>> ? (192.168.0.247) at <incomplete> on eno1
>> heating-controller (192.168.0.201) at b8:27:eb:c3:31:3d [ether] on eno1
>> ? (192.168.0.27) at <incomplete> on eno1
>> ? (192.168.0.203) at <incomplete> on eno1
>> ? (192.168.0.180) at <incomplete> on eno1
>> ? (192.168.0.83) at <incomplete> on eno1
>> cymbeline (192.168.0.100) at 08:62:66:4a:85:d8 [ether] on eno1
>> ? (192.168.0.102) at 3c:a8:2a:f6:3a:c8 [ether] on eno1
>> ? (192.168.0.16) at <incomplete> on eno1
>> ? (192.168.0.227) at <incomplete> on eno1
>> ? (192.168.0.11) at <incomplete> on eno1
>> ? (192.168.0.239) at <incomplete> on eno1
>> ? (192.168.0.28) at <incomplete> on eno1
>>
>> The incomplete entries are for IP addresses I simply never have used.
>>
>> Anyone recognise this behaviour?
>>
>> After clearing, at least one is back...
> 
>    This could be a case of your router remembering
>    where DHCP addresses USED to be. Even if you later
>    set the devices to static, the old associations
>    are't necessarily cleared. ARP may just be
>    smelling traces of the missing devices.

Er no. This cache existed in the desktop computer only, not the router, 
at all.
And its nothing to do with DHCP.

Its an ARP cache. Not DHCP.

-- 
"The most difficult subjects can be explained to the most slow witted 
man if he has not formed any idea of them already; but the simplest 
thing cannot be made clear to the most intelligent man if he is firmly 
persuaded that he knows already, without a shadow of doubt, what is laid 
before him."

    - Leo Tolstoy

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Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-12 11:30 +0100
  Re: Spurious ARP entries... Robert Heller <heller@deepsoft.com> - 2025-07-12 10:36 +0000
    Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-12 11:52 +0100
  Re: Spurious ARP entries... Andy Burns <usenet@andyburns.uk> - 2025-07-12 11:41 +0100
    Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-12 11:54 +0100
      Re: Spurious ARP entries... Andy Burns <usenet@andyburns.uk> - 2025-07-12 12:14 +0100
        Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-12 13:06 +0100
          Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-13 01:20 +0000
            Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-13 00:16 -0400
              Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-13 12:01 +0100
                Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-13 22:10 +0000
                Re: Spurious ARP entries... "Carlos E.R." <robin_listas@es.invalid> - 2025-07-14 10:19 +0200
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-14 14:54 +0100
                Re: Spurious ARP entries... "Carlos E.R." <robin_listas@es.invalid> - 2025-07-15 11:58 +0200
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-15 15:20 +0100
                Re: Spurious ARP entries... "Carlos E.R." <robin_listas@es.invalid> - 2025-07-16 11:21 +0200
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-16 16:46 +0100
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-15 22:10 -0400
  Re: Spurious ARP entries... Richard Kettlewell <invalid@invalid.invalid> - 2025-07-12 11:43 +0100
    Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-12 12:02 +0100
  Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-12 19:33 -0400
    Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-13 11:52 +0100
      Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-14 00:08 -0400
  Re: Spurious ARP entries... Shadow <Sh@dow.br> - 2025-07-12 21:29 -0300
    Re: Spurious ARP entries... Robert Heller <heller@deepsoft.com> - 2025-07-13 00:55 +0000
      Re: Spurious ARP entries... Andy Burns <usenet@andyburns.uk> - 2025-07-13 06:35 +0100
        Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-13 02:30 -0400
          Re: Spurious ARP entries... John Ames <commodorejohn@gmail.com> - 2025-07-14 08:06 -0700
            Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-14 22:05 +0000
              Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-15 22:21 -0400
                Re: Spurious ARP entries... Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2025-07-16 15:53 +0000
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-16 19:19 +0100
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 03:13 -0400
              Re: Spurious ARP entries... John Ames <commodorejohn@gmail.com> - 2025-07-16 08:05 -0700
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-16 16:47 +0100
                Re: Spurious ARP entries... John Ames <commodorejohn@gmail.com> - 2025-07-16 09:02 -0700
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-16 19:17 +0100
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 03:10 -0400
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 03:08 -0400
                Re: Spurious ARP entries... Richard Kettlewell <invalid@invalid.invalid> - 2025-07-16 19:18 +0100
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-16 19:21 +0100
                Re: Spurious ARP entries... Pancho <Pancho.Jones@protonmail.com> - 2025-07-16 19:41 +0100
                Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-17 02:15 +0000
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 03:38 -0400
                Re: Spurious ARP entries... Pancho <Pancho.Jones@protonmail.com> - 2025-07-17 09:29 +0100
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-17 09:46 +0100
                Re: Spurious ARP entries... Pancho <Pancho.Jones@protonmail.com> - 2025-07-17 10:39 +0100
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 22:53 -0400
                Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-18 05:50 +0000
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-18 02:11 -0400
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 22:42 -0400
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-18 11:05 +0100
                Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-18 23:19 +0000
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-18 23:06 -0400
                Re: Spurious ARP entries... Pancho <Pancho.Jones@protonmail.com> - 2025-07-19 10:50 +0100
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 03:15 -0400
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-17 09:50 +0100
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 22:48 -0400
                Re: Spurious ARP entries... John Ames <commodorejohn@gmail.com> - 2025-07-18 09:02 -0700
                Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-18 05:48 +0000
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 03:41 -0400
                Re: Spurious ARP entries... Richard Kettlewell <invalid@invalid.invalid> - 2025-07-17 11:19 +0100
                Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-17 22:58 -0400
                Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-17 02:14 +0000
                Re: Spurious ARP entries... John Ames <commodorejohn@gmail.com> - 2025-07-17 07:52 -0700
                Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-17 19:59 +0100
                Re: Spurious ARP entries... Lawrence D'Oliveiro <ldo@nz.invalid> - 2025-07-18 05:47 +0000
            Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-15 22:20 -0400
  Re: Spurious ARP entries... jayjwa <jayjwa@atr2.ath.cx.invalid> - 2025-07-13 13:03 -0400
    Re: Spurious ARP entries... The Natural Philosopher <tnp@invalid.invalid> - 2025-07-13 21:46 +0100
      Re: Spurious ARP entries... vallor <vallor@cultnix.org> - 2025-07-13 22:14 +0000
      Re: Spurious ARP entries... c186282 <c186282@nnada.net> - 2025-07-14 00:10 -0400

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