ip routing command issue

[mahesh18]

hi all,

need to know this

i have layer 3 switch running different vlans and it has no ip protocol running.

should i  issue ip routing command there or not?

this switch has connection to another switch which is also layer 3 and that switch also has no ip protocol running.

let me know when we use ip routing command in device config ?

1>when we use layer  3 device with different vlans

or

when we user layer 3 device and running ip protocol as rip or ospf

thanks

mahesh

[cadet alain]

Hi mahesh,

from your output you haven't got ip routing enabled and no default gateway configured.

But to rule out the proxy arp solution we need sh arp output  for 4.2.2.2 .

Regards.

Alain.

[Richard Burts]

Alain

There is already the output of show arp in a previous post in this thread. Here are those results

3550SMIB#sh ip arp 4.2.2.2
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  4.2.2.2                96   0000.0c07.ac01  ARPA   Vlan10

I believe that this is clear evidence that the switch is using ARP for 4.2.2.2 and the mac address from the response is clearly a layer 3 Cisco device which is running HSRP.

So I believe this is sufficient to answer the issue in this thread. The switch does not have IP routing enabled and does not have a default gateway configured (or active). So the switch is using ARP for the Internet address of 4.2.2.2 and the connected layer 3 device does have proxy arp enabled.

HTH

Rick

[mahesh18]

Hi Rick,

Thanks for the reply

here is output of previous post which is replied to swati

i am putting again so you guys can see it and confirm

hi swati ,

i  did as per your request

3550SMIB#sh ip arp 4.2.2.2
Protocol   Address          Age (min)  Hardware Addr   Type   Interface
Internet   4.2.2.2                96   0000.0c07.ac01  ARPA   Vlan10

3550SMIB#sh  mac add
3550SMIB#sh mac address-table add
3550SMIB#sh mac  address-table address  0000.0c07.ac01
          Mac Address Table
-------------------------------------------

Vlan     Mac Address       Type        Ports
----    -----------        --------    -----
  10    0000.0c07.ac01    DYNAMIC     Gi0/2
Total  Mac Addresses for this criterion: 1

3550SMIB#sh cdp nei gi0/2
Capability  Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                   S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

Device  ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
3550SMIA          Gig 0/2           123          R S I     WS-C3550- Gig 0/2

3550SMIB#3550SMIA
Trying  3550SMIA (192.168.5.2)... Open

User Access Verification

Username:

Password:
3550SMIA#sh  mac add
3550SMIA#sh mac address-table add
3550SMIA#sh mac  address-table address 0000.0c07.ac01
          Mac Address Table
-------------------------------------------

Vlan     Mac Address       Type        Ports
----    -----------        --------    -----
  10    0000.0c07.ac01    STATIC      CPU
Total  Mac Addresses for this criterion: 1

so this mac address is of HSRP   config on layer 3 switch A.

Layer 3 switch A ___________________________has  connection to Router.

Switch B is running HSRP  and is in standby state .

Switch A is active.

[Richard Burts · Accepted solution]

Mahesh

I appreciate your posting this output again. But I wonder why you thought it would be helpful. As I said in my recent post I believe that we have a correct explanation for your situation. The output makes it very clear that your switch is able to ping 4.2.2.2 because it has done an ARP for that address and the connected layer 3 device has responded to the ARP request with its MAC address (0000.0c07.ac01) which is pretty clearly the MAC of a Cisco layer 3 device which is running HSRP on its interface.

So your switch sent the ARP request for 4.2.2.2 and the connected layer 3 device responded because it has enabled proxy arp. Is there anything in this that is not clear to you? If so please restate your question so that we can respond to it.

HTH

Rick

[sdheer · Accepted solution]

Hi Mahesh,

I second Rick on the same.

From the outputs its evident  that router has proxy ARP enabled.

[mahesh18]

Hi Rick and swati,

Many thanks for great explanation on this.

regards

mahesh

[cadet alain]

Hi Richard,

There is already the output of show arp in a previous post in this thread. Here are those results

Sorry I had missed that one.

Regards.

Alain.