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MAC to IP

Manoj Reddy
Level 1
Level 1

Hi, we have an end device ABC - name changed as it's a production network, and we usually configure this device in VLAN 921, and below is port 23 from the access switch that learning dynamic IP from VLAN 921

 

switch#sh mac-address-table int Gi1/0/23
Mac Address Table
-------------------------------------------

Vlan Mac Address Type Ports
---- ----------- -------- -----
921 5852.8af5.c0b1 DYNAMIC Gi1/0/23
Total Mac Addresses for this criterion: 1

 

I went to the distribution switch where we have the VRF 7010 configured, but when I tried checking that particular MAC it's not learning any IP we have the IP address reservation mentioned correctly and DHCP scope is available.

We have the same setup for other end devices which are part of the same VLAN and same VRF those are working fine. Please let me know what could be the problem, as of now the end machine is not working 

 

switch#sh ip arp vrf 7010 | in 5852.8af5.c0b1
switch#

3 Replies 3

balaji.bandi
Hall of Fame
Hall of Fame

The first thing comes into my mind was is the VLAN 921 on this switch part of the VRF?

 

Can you compare the working switch VLAN 921 SVI config with this SVI config?

 

BB

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Hi Balaji,

Thanks, for the time in responding to my post.

To add, yes VLAN 921 is a part of VRF 7010.

I have 3 ports in the access switch which is a part of VLAN 921 as you can see below, 

921 ABC active Gi1/0/23, Gi2/0/8, Gi3/0/1

The port Gi2/0/8, same goes with Gi3/0/1 both are working only Gi1/0/23 is not learning any IP even though it's learning the MAC

Dis switch #sh ip arp vrf 7010 | in 0800.7045.dfa3   - the output is for Gi2/0/8

Internet 10.5.118.92 28 0800.7045.dfa3 ARPA Vlan921

 

the below is for Gi1/0/23

 

Dis switch#sh mac address-table address 5852.8af5.c0b1
Mac Address Table
-------------------------------------------

Vlan Mac Address Type Ports
---- ----------- -------- -----
921 5852.8af5.c0b1 DYNAMIC Po27
Total Mac Addresses for this criterion: 1

 

PO27 is connected to the access switch 
dis switch#
dis switch#sh IP ar
dis switch#sh ip arp vrf
dis switch#sh ip arp vrf 7010 | in 5852.8af5.c0b1

Are you sure that the device connected on 1/0/23 is working correctly? Can you post the output of ipconfig (or similar command if not Windows). After getting ipconfig have the device ping something, and then check your switch arp table again.

HTH

Rick
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