Re: Clear IP arp?

Well I guess I just learned something new then! Thanks for the debug output,
very helpful.
On Sep 26, 2011 6:51 AM, "garry baker" <baker.garry_at_gmail.com> wrote:
> seems that is the case...
>
> i never really thought about what this command was doing, but have
> seen it and used it so much in enterprise networks on core devices
> when swapping out computers and working with dhcp...
>
> the little things that just sort of skip over i guess...
>
> R1#sh debug
> ARP:
> ARP packet debugging is on
>
> R1#sh ip arp
> Protocol Address Age (min) Hardware Addr Type Interface
> Internet 12.12.12.1 - c200.177c.0000 ARPA FastEthernet0/0
> Internet 12.12.12.2 50 c202.177c.0000 ARPA FastEthernet0/0
>
> R1#clear ip arp 12.12.12.2
>
> R1#
> *Mar 1 20:58:04.962: IP ARP: sent req src 12.12.12.1 c200.177c.0000,
> dst 12.12.12.2 c202.177c.0000 FastEthernet0/0
> *Mar 1 20:58:05.030: IP ARP: rcvd rep src 12.12.12.2 c202.177c.0000,
> dst 12.12.12.1 FastEthernet0/0
> *Mar 1 20:58:05.034: IP ARP: creating entry for IP address:
> 12.12.12.2, hw: c202.177c.0000
>
> R1#sh ip arp
> Protocol Address Age (min) Hardware Addr Type Interface
> Internet 12.12.12.1 - c200.177c.0000 ARPA FastEthernet0/0
> Internet 12.12.12.2 0 c202.177c.0000 ARPA FastEthernet0/0
>
> --
> Garry L. Baker
>
> "With sufficient thrust, pigs fly just fine..." - RFC 1925
>
>
>
> On Mon, Sep 26, 2011 at 4:41 PM, Steve Di Bias <sdibias_at_gmail.com> wrote:
>> Interesting info, does the same hold true when clearing individual ARP
>> entries with the "clear ip arp x.x.x.x" command?
>> On Sep 26, 2011 6:25 AM, "Joe Astorino" <joeastorino1982_at_gmail.com>
wrote:
>>> Indeed, I learned this and posted on it here a few months ago as well.
>> When
>>> you do "clear ip arp" it actually will look at every entry currently in
>> the
>>> table and send out an ARP for it, thereby refreshing the table. The only
>>> way I know of to truly clear it is shut and no shut the interface.
>>>
>>> On Sun, Sep 25, 2011 at 12:50 PM, Nadeem Rafi <nrafia_at_gmail.com> wrote:
>>>
>>>> it does not clear cache at all, it just refresh it :)
>>>> for detail check this link
>>>> http://nadeemrafi.com/arp-arpa-and-snap-wow-110/
>>>>
>>>> On Sun, Sep 25, 2011 at 7:31 PM, Ted Sell <tedsell_at_gmail.com> wrote:
>>>>
>>>> > I have a few questions:
>>>> > Why does the clear command not work as expected?
>>>> > I tried to clear the arp-cache using the clear command. I watched a
INE
>>>> > video where the instructor tried the clear command, without success.
He
>>>> had
>>>> > to shut and no shut the interface to get the cache to to clear for
the
>>>> > interface.
>>>> > What does the clear command do when you're trying to clear the
>> ARP-cache?
>>>> > TIA,
>>>> > Ted Schafer
>>>> >
>>>> >
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>>>>
>>>>
>>>
>>>
>>> --
>>> Regards,
>>>
>>> Joe Astorino
>>> CCIE #24347
>>> Blog: http://astorinonetworks.com
>>>
>>> "He not busy being born is busy dying" - Dylan
>>>
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>>
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Received on Mon Sep 26 2011 - 07:06:54 ART