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Pakets destined to different ip destinations seen on the same switch port

giaaaj
Level 1
Level 1

Hallo all

I am using a WS-C4948 to connect many subnets in different vlans. The 27 bit subnets contain customer servers and one of these subnets conatains 3 "DataDomain Servers" 2 of them have more than one interface in this subnet. The customer-servers backup there Data to the DataDomain servers unsing NFS or Windows shares. See the Network diagram attached

The DataDomain Servers are

CISS012 - Interface 26 - IP 172.18.0.14/27.

CISS012 - Interface 44 - IP 172.18.0.13/27.

CISS013 - Interface PO1 - IP 172.18.0.15/27.

CISS013 - Interface 41 - IP 172.18.0.16/27.

CISS902 - Interface 42 - IP 172.18.0.19/27.

The problem that i have is that exactly the same pakets are being received on interface 26 and 41. I done the following test:

I have configured 2 span ports to receive the data from pots 26 and 41 separetly and connected to notebooks to the span ports, startted wireshark and can see that

- The data destined to 172.18.0.16 and the data destined to 172.18.0.14 are being received on both interfaces 26 and 41.

Is the any idea what the problem could b

5 Replies 5

Laurent Aubert
Cisco Employee
Cisco Employee

Hi,

Maybe the mac table for VLAN 400 is corrupted somehow. Did you try to clear it to refresh the entries ?

What happens when you ping one of the host from COREG006 ?

HTH

Laurent.

Hi Laurent,

Thanks for answering

I have done the following tests

1- Pings from COREG006 or COREG206 -> 172.18.0.16 are seen only on int 41 ( the system 172.18.0.16 is connected to interface 41).

2- Pings from COREG006 or CORG206-> 172.18.0.14 are seen only on int 20 ( the system 172.18.0.14 is connected to interface 20).

3- Pings form system MMDLU009 (connected to COREH060 / Port2 ) directed to 172.18.0.14 are seen on both interfaces 20 & 41.

4- Pings form systems MMDLU009 directed to 172.18.0.16 are seen on both interfaces 20 & 41.

5- Pings form system HABSAP10 ( connected to COREG006 / port 11) directed to 172.18.0.16 are seen on both interfaces 20 & 41.

6- Pings form system HABSAP10 directed to 172.18.0.14 are seen on both interfaces 20 & 41.

Thanks for your effort.

Ali

giaaaj
Level 1
Level 1

Hier are some traces that i have done.

20-ping-mm-hab.pcap: The trace conatains wireshark data collected from Port 20 and the pings were done form 2 different systems to the ips 172.18.0.14 & 172.18.0.16.

Hier are some traces that i have done.

41-ping-mm-hab.pcap : The trace conatains wireshark data collected from Port 41 and the pings were done form 2 different systems to the ips 172.18.0.14 & 172.18.0.16.

Hi,

destination mac addresses look fine so you should check the mac table for this VLAN to see if there is no corrupted entry.

Don't hesitate to clear it and may be if it's possible shut/no shut the ports...

HTH

Laurent.

Laurent,

I have cleared the mac table, still have the same problem.

I made further tests and found the the traffic is being received on all interfaces in vlan 400.

I am planing to reboot COREG006 and coreg206. Not sure what to do next!!

I 'll be graet if you can give an idea what to do next.

Thanks

Ali

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