[j-nsp] proxy arp C vs J

[Alex Arseniev]

Did you check what MACs are used in 1st, 2nd and 3rd time? Specifically MAC 
OUIs.
I suspect this is a side effect of having C-J in the same broadcast domain.
Basically, when J-interface ARPs for a connected host, _AND_ if C has a 
specific route to that host/32, the C will answer with own MAC.
I have seen this myself many times and I suggest to disable proxy-arp on C 
to get rid of this behavior.
HTH
Thanks
Alex

----- Original Message ----- 
From: "biwa net" <biwa2go at gmail.com>
To: <juniper-nsp at puck.nether.net>
Sent: Monday, February 06, 2012 7:57 PM
Subject: Re: [j-nsp] proxy arp C vs J


> Forgot to add we are running MX80 on Junos 11.2
>
> On 6 February 2012 19:56, biwa net <biwa2go at gmail.com> wrote:
>
>> Hi Guys
>> We are experiencing some issues in one of our client sites,
>>
>> Basically we migrate from a Cisco to a Juniper MX80, and since there has
>> been some issues,  mainly we are seeing IP addresses being shared by 2-3
>> mac address, to be precise , mac address being rewritten , ie: one IP is
>> being seen on the Juniper owned by 3 different mac address within one 
>> hour
>> (  the 1st mac address is being re-writen by the 2nd one and then 2nd by
>> the 3rd mac).
>>
>> This is causing a lot of users not having any kind of internet
>> connectivity.When we rollback to the Cisco device , this issue does not
>> occur.
>>
>> After investigation we can safely eliminates the DHCP server being the
>> cause of issue (, also proved when Cisco is roll back in the topology),
>>
>> The config of the Cisco is fairly simple and is almost 99.99% than the 
>> one
>> being copied over to the Juniper.
>>
>> One thing we notice is that both Cisco and Juniper has proxy-arp
>> configured on some of the interface, and we are planning in our next
>> maintenance to disable it.
>>
>> my question is: is the proxy-arp behavior in Juniper slightly different
>> than the Cisco ?
>>
>> thanks for your inputs
>>
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