Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Cisco > Thief MAC ADDRESS

Reply
Thread Tools

Thief MAC ADDRESS

 
 
ns
Guest
Posts: n/a
 
      03-03-2005
Hi all,

I have two cisco routers and one windows server. All is connected to the
catalyst 4006 (L3 Router) :

ROUTER_A
SERVER_A
ROUTER_Z
SWITCH_4006

When SERVER_A need to talk with ROUTER_A via SWITCH_4006. The SWITCH_4006
receive ARP response from ROUTER_Z talking that the MAC address of SERVER_A
is his MAC address !!! why !!???

I confirme that each network interface has it MAC address !!

So, bad mac address is allocated on the SWITCH_4006.
On the same time, i can see on the SWITCH_4006 the real MAC address of
ROUTER_Z !!

So, this problem cause packet lost between SERVER_A and ROUTER_A

Can you help me please !!???

ThankYou very mych.

Best Regards
NS




 
Reply With Quote
 
 
 
 
Phillip Remaker
Guest
Posts: n/a
 
      03-03-2005

"ns" <(E-Mail Removed)> wrote in message news:(E-Mail Removed)...
> I have two cisco routers and one windows server. All is connected to the
> catalyst 4006 (L3 Router) :
>
> ROUTER_A
> SERVER_A
> ROUTER_Z
> SWITCH_4006
>
> When SERVER_A need to talk with ROUTER_A via SWITCH_4006. The SWITCH_4006
> receive ARP response from ROUTER_Z talking that the MAC address of
> SERVER_A
> is his MAC address !!! why !!???


Typically, this happens when the subnet mask is set incorrect on the router
inteface, or there are mismatched secondary addresses. A router will
respond with its MAC address in proxy for an IP address. If it receives an
ARP request for a device on another interface, it will answer that ARP in
order to facilitate routing.

You can turn it off:

interface (mumble)
no ip proxy-arp

But, if the reply is happening, you probably have some kind of address/mask
mixup, or an interface plugged into the wrong LAN or VLAN.


Need more details, like configuration....


 
Reply With Quote
 
 
 
 
ns
Guest
Posts: n/a
 
      03-08-2005
Hi all,

- The subnet mask is correct

- I don't have secondary address on the router but i have two FastEthernet
interfaces. The router is used as gateways between two physical networks.

I will try the command "no ip proxy-arp" on the interface but i don't
understund why the router is identified as owner of mac address searched !

ThankYou very much Phillip for your help
I will let you know a bout tests.

Best Regards
NS


"Phillip Remaker" <(E-Mail Removed)> a écrit dans le message
de news:%dIVd.2309$(E-Mail Removed) ...
>
> "ns" <(E-Mail Removed)> wrote in message news:(E-Mail Removed)...
> > I have two cisco routers and one windows server. All is connected to the
> > catalyst 4006 (L3 Router) :
> >
> > ROUTER_A
> > SERVER_A
> > ROUTER_Z
> > SWITCH_4006
> >
> > When SERVER_A need to talk with ROUTER_A via SWITCH_4006. The

SWITCH_4006
> > receive ARP response from ROUTER_Z talking that the MAC address of
> > SERVER_A
> > is his MAC address !!! why !!???

>
> Typically, this happens when the subnet mask is set incorrect on the

router
> inteface, or there are mismatched secondary addresses. A router will
> respond with its MAC address in proxy for an IP address. If it receives

an
> ARP request for a device on another interface, it will answer that ARP in
> order to facilitate routing.
>
> You can turn it off:
>
> interface (mumble)
> no ip proxy-arp
>
> But, if the reply is happening, you probably have some kind of

address/mask
> mixup, or an interface plugged into the wrong LAN or VLAN.
>
>
> Need more details, like configuration....
>
>



 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Differnce between setting mac address port security under theinterface vs. the mac address-table global command ttripp Cisco 5 02-05-2010 10:49 PM
OT: Thief with no clue catwalker63 MCSE 0 04-02-2005 01:51 AM
To catch a Thief. Ant Computer Support 20 09-21-2004 10:42 PM
Thief Market LCT Digital Photography 1 10-01-2003 05:01 PM
DVD Verdict reviews: THE GOOD THIEF, VENOM, DARK BLUE, and more! DVD Verdict DVD Video 0 09-04-2003 09:04 AM



Advertisments