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0000.0000.0000 MAC Addresses in ARP Table.

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Anonymous
June 6, 2005 10:04:04 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Hello all
I have this Juniper ERX in my network
What i'm worry about are the 0000.0000.0000 MAC Addresses that are
present in the Arp Table

Does anyone know why?
Regards
ws00sw

plc-bras#show ver
Juniper Edge Routing Switch ERX-1400
Copyright (c) 1999-YYY5 Juniper Networks, Inc. All rights reserved.
System Release: erx_5-3-3p0-8.rel
Version: 5.3.3 patch-0.8 [BuildId 3397] (April 8, YYY5
09:11)
System running for: 0 days, 10 hours, 54 minutes, 9 seconds
(since FRI JUN 03 YYY5 00:24:30 GMT-4)

slot state type admin spare running release slot uptime
---- ------- -------- ------- ----- ----------------- -------------
0 online GE enabled --- erx_5-3-3p0-8.rel 0d10h:43m:19s
1 --- --- --- --- --- ---
2 --- --- --- --- --- ---
3 --- --- --- --- --- ---
4 --- --- --- --- --- ---
5 --- --- --- --- --- ---
6 online SRP-10Ge enabled --- erx_5-3-3p0-8.rel 0d10h:52m:32s
7 standby SRP-10Ge enabled --- erx_5-3-3p0-8.rel ---
8 --- --- --- --- --- ---
9 online OC12Atm enabled --- erx_5-3-3p0-8.rel 0d10h:44m:00s
10 --- --- --- --- --- ---
11 --- --- --- --- --- ---
12 online OC12Atm enabled --- erx_5-3-3p0-8.rel 0d10h:43m:59s
13 --- --- --- --- --- ---
Copyright (c) 1999-YYY5 Juniper Networks, Inc. All rights reserved.

plc-bras#sh ip arp | i 0000.0000.0000
Please wait....
YYY.XXX.47.5 21450 0000.0000.0000 ATM9/0.971329
YYY.XXX.230.53 21420 0000.0000.0000 ATM9/0.971174
YYY.84.76.183 21230 0000.0000.0000 ATM12/0.800514
YYY.84.78.111 21250 0000.0000.0000 ATM12/0.1380742
YYY.90.127.101 21390 0000.0000.0000 ATM12/0.1350785
YYY.XXX.62.153 21530 0000.0000.0000 ATM12/0.2180776
YYY.XXX.62.246 21480 0000.0000.0000 ATM12/0.1381051
YYY.XXX.62.247 21480 0000.0000.0000 ATM12/0.1410570
Anonymous
June 6, 2005 8:41:07 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <1118063044.332407.212430@g49g2000cwa.googlegroups.com>,
<ws00sw@gmail.com> wrote:
:I have this Juniper ERX in my network
:What i'm worry about are the 0000.0000.0000 MAC Addresses that are
:p resent in the Arp Table

:D oes anyone know why?

This has been discussed in the last couple of days in
comp.protocols.tcp-ip
--
"Who Leads?" / "The men who must... driven men, compelled men."
"Freak men."
"You're all freaks, sir. But you always have been freaks.
Life is a freak. That's its hope and glory." -- Alfred Bester, TSMD
Anonymous
June 7, 2005 2:00:20 AM

Archived from groups: comp.dcom.lans.ethernet (More info?)

"Walter Roberson" <roberson@ibd.nrc-cnrc.gc.ca> wrote:
>
> <ws00sw@gmail.com> wrote:
> :I have this Juniper ERX in my network
> :What i'm worry about are the 0000.0000.0000 MAC Addresses that are
> :p resent in the Arp Table
>
> :D oes anyone know why?
>
> This has been discussed in the last couple of days in
> comp.protocols.tcp-ip

I think that discussion was about 0.0.0.0 IPv4 addresses, not about
00-00-00-00-00-00 MAC addresses. This question, about MAC addresses,
belongs in this usenet group.

In general, unless I'm forgetting something from some distant past, an
all 0s *IP* source address is valid for any unconfigured host. So for
example, a DHCP, BOOTP, or RARP request from an unconfigured host would
have an all 0s IP Source (or "Client") Address, a valid MAC Source
Address, and an all 1s MAC destination address. With no prior
information, that client should be able to find a machine that can
assign it a valid IP address, which is then mapped one to one with the
IP address on that IP subnet. So all 0s IP addresses are well
documented.

But an all 0s MAC address is an unstandard anomaly. It was used by Sun,
IIRC, as a broadcast destination address, instead of the standard all 1s
MAC DA, but that's irrelevant to the ARP table.

If MAC addresses 0 appear in the ARP table, perhaps that's the result of
a non-standard protocol called "unARP"? Which is, if a host decides to
go offline, it can send an unARP message to tell every other host in the
subnet that IP address w.x.y.z is now no longer tied to a particular MAC
address. So it can be reused without waiting for an ARP timeout period.

I'm just guessing that maybe you have unARP hosts in your network?

Bert
Related resources
Anonymous
June 22, 2005 2:46:43 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Walter, can you please show me the link
Thanks
Regards


Walter Roberson ha escrito:
> In article <1118063044.332407.212430@g49g2000cwa.googlegroups.com>,
> <ws00sw@gmail.com> wrote:
> :I have this Juniper ERX in my network
> :What i'm worry about are the 0000.0000.0000 MAC Addresses that are
> :p resent in the Arp Table
>
> :D oes anyone know why?
>
> This has been discussed in the last couple of days in
> comp.protocols.tcp-ip
> --
> "Who Leads?" / "The men who must... driven men, compelled men."
> "Freak men."
> "You're all freaks, sir. But you always have been freaks.
> Life is a freak. That's its hope and glory." -- Alfred Bester, TSMD
Anonymous
June 22, 2005 10:04:56 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <1119462403.922683.174220@g43g2000cwa.googlegroups.com>,
<ws00sw@gmail.com> top-posted:

|Walter Roberson ha escrito:
|> In article <1118063044.332407.212430@g49g2000cwa.googlegroups.com>,
|> <ws00sw@gmail.com> wrote:

|> :What i'm worry about are the 0000.0000.0000 MAC Addresses that are
|> :p resent in the Arp Table

|> This has been discussed in the last couple of days in
|> comp.protocols.tcp-ip

|Walter, can you please show me the link

http://groups.google.ca/group/comp.protocols.tcp-ip/msg...

"Can ARP packet have zero or Broadcast address as Soure IP address??"
[sic]
--
Any sufficiently old bug becomes a feature.
Anonymous
June 22, 2005 10:27:53 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <d9c988$8ob$1@canopus.cc.umanitoba.ca>,
Walter Roberson <roberson@ibd.nrc-cnrc.gc.ca> wrote:
>In article <1119462403.922683.174220@g43g2000cwa.googlegroups.com>,
> <ws00sw@gmail.com> top-posted:
>
>|Walter Roberson ha escrito:
>|> In article <1118063044.332407.212430@g49g2000cwa.googlegroups.com>,
>|> <ws00sw@gmail.com> wrote:
>
>|> :What i'm worry about are the 0000.0000.0000 MAC Addresses that are
>|> :p resent in the Arp Table
>
>|> This has been discussed in the last couple of days in
>|> comp.protocols.tcp-ip
>
>|Walter, can you please show me the link
>
>http://groups.google.ca/group/comp.protocols.tcp-ip/msg...
>
>"Can ARP packet have zero or Broadcast address as Soure IP address??"
>[sic]
>--
>Any sufficiently old bug becomes a feature.

That discussion was about an IP address of zero. If you are seeing a MAC
address of zero, that would be a different situation. If I recall correctly,
we once had a problem with a system where the battery holding the ram that
contained the MAC address has died. The system tried to use a MAC address
of zero, which caused problems. I forget now the exact problems caused.
--
Tom Schulz
schulz@adi.com
January 16, 2009 6:58:31 AM

Hi

Not sure how the junipers arp table but I am looking at a problem at the moment where we are not getting a response from a node on a wireless network - whilst we are waiting for the arp response the mac address entry in the arp table is set to all zeros.

Does anyone know whether windows has a minimum period during which it will not answer another arp from the same host - just wondering if we need to up the period that we hold entries in our table for.

Regards

Shaun
shoobster+tomshardware/at/gmail.com
!