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Community Member

Server connected to switchport

                   Hi Everyone,

Seems i am tracing server connection on switch   i do the ping from directly connected switch where server is connected.

sh ip arp 192.168.20.10

Protocol  Address          Age (min)  Hardware Addr   Type   Interface

Internet  192.168.98.10             3   0019.b9d1.d4a5  ARPA   Vlan27

I can see the mac address of the server  is 0019.b9d1.d4a5.

When i do

#sh mac address-table address 0019.b9d1.d4a5
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
27    0019.b9d1.d4a5    DYNAMIC     Gi1/1
47    0019.b9d1.d4a5    DYNAMIC     Gi1/0/25

i traced the server is directly connected to the switch port Gi1/1.

Need to confirm that sh ip arp shows how switch see how server is connected layer 3 wise and  sh mac add table addess shows how switch is learning server mac  as layer 2 wise right?

Regards

MAhesh

6 REPLIES
VIP Purple

Server connected to switchport

Hi Mahesh,

"show ip arp " will provide you the IP address mapping to MAC addresses whereas "show mac address-table" gives you from which switch port the MAC address is learning from & whether it is static or dynamically learn MAC address.

In your case why same MAC address learn via two different switch ports  on two different vlan ?

HTH

Rasika

Community Member

Server connected to switchport

Hi Rasika,

Seems  then both commands are provinding the layer 2 info.

i am trying to find why switch is learning mac from two different ports

Regards

Mahesh

VIP Purple

Re: Server connected to switchport

Looks like your sever having multiple connections. I would physically inspect the server end & ensure how many cables connect back to network. In that way ensure which physical port it should learn in normal condition.

Then if you suspect other port is wrong (eg G1/0/25) see what is connected to G1/0/25 physically. trace it back to see where it end up with.

HTH

Rasika

Community Member

Server connected to switchport

Hi Rasika,

Seems server vlan is bridged to Transparent Firewall vlan.

So second vlan is of transparent fw.

As transparent fw is layer to only

Regards

Mahesh

VIP Purple

Re: Server connected to switchport

Are you having an issue with this ? I would think if you see a MAC address learning from two different switchport switch will get confused where to forward the traffic (MAC address instability)

Community Member

Server connected to switchport

No issues i was trying to trace the path from server to its gateway in order to find how many firewalls are in between as

i need to open ACL.

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