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sg300 duplicate mac address in native vlan

m.j.gritli
Level 1
Level 1

Dear Ciscos,

Good Day...

i've noticed something wrong on a network i was assigned to tshoot.

the network is connected as follows using a wireless p2p .. all access switches are Cisco SG300-28 , top 2 cores are Cisco 3560

when issuing the "show mac address-table" command, i see mac address being copied to vlan 1 which may indicate a Layer 2 loop.

i've tried everything , STP works fine , switch no2 is the root on all other switches. but, problem still exists...

Thank for help

3 Replies 3

marioesp
Level 1
Level 1

Greetings,

can you provide more information about this scenario? which mac address is duplicated? if there any loop?

Mario Espinoza
.:|:.:|:. Cisco Small Business TAC
Email: marioesp@cisco.com
Shift Hours: Monday - Friday from 9:30 AM – 7:00 PM (EST)

Most of our Product documentation and Solutions to commonly asked questions can be found at
http://www.cisco.com/go/smallbizsupport

Cisco Support Frontline Phone Number: +1 866-606-1866
Cisco Support Worldwide Contacts:
https://www.cisco.com/c/en/us/support/web/tsd-cisco-small-business-support-center-contacts.html

thank you for your reply, as you may of noticed , this topology is loop free , it's not doing any Layer2 redundancy .. but one more thing to add , it's connected over Wireless, this is a small ISP topology, so from switch 3 down, it's all connected via "UBI-QUITY" wireless Links , thus all clients mac-address are found duplicated in all vlans, although they're supposed to be in clan 80 only...

this is my first time to witness such a thing ..

thank again

Thank for reply,

can you tell me on which switch does Wireless AP is plugged? can you attach some print shoot to see the duplicated mac address?

Mario Espinoza
.:|:.:|:. Cisco Small Business TAC
Email: marioesp@cisco.com
Shift Hours: Monday - Friday from 9:30 AM – 7:00 PM (EST)

Most of our Product documentation and Solutions to commonly asked questions can be found at
http://www.cisco.com/go/smallbizsupport

Cisco Support Frontline Phone Number: +1 866-606-1866
Cisco Support Worldwide Contacts:
https://www.cisco.com/c/en/us/support/web/tsd-cisco-small-business-support-center-contacts.html