APR Table on Switch 2960X incorrect

[jakkrit01]

Hi All

According to I make two interface VLAN on switch model WS-C2960X-24TS-LL, first Defalt vlan (vlan1) for management and second (vlan100) for guest, both vlan no routing together and this switch is a DHCP server for only vlan100

A point of problem,

IP management (vlan1) in this switch some time ping timeout, and I check in the arp table it is incorrect, please focus in picture you will see some time subnet 172.x.x.x are vlan 100 some time 172.x.x.x are vlan 1 (actually 172.x.x.x are vlan 100 and 10.x.x.x are vlan 1)

Please help, I try to solve this problem in 3 day but I can't 

[Krishan]

Please can you look to the configuration of Interface gi0/1? If this Interface is in Access and Default VLAN is changed from VLAN Id 1 to VLAN Id 100? Compare the settings with Interface gi0/2 by looking with "show running-config".

[jakkrit01]

 Hi  Krishan,

Thanks for you respond,

Please can you look to the configuration of Interface gi0/1?

-->> Interface Gi0/1 is in access vlan 1 

If this Interface is in Access and Default VLAN is changed from VLAN Id 1 to VLAN Id 100?

--> No can't change from VLAN1 to VLAN100 because this interface connecting to Gateway of vlan 1 (Gateway is Firewall), VLAN100 is guest VLAN and, my design VLAN100 different gateway with VLAN1  

Compare the settings with Interface gi0/2 by looking with "show running-config".

-->interface Gi0/1 is same configuration with Gi0/2,  I'm attach picture in this post

[Krishan]

From your previous pictures I have seen that mac address/ ip address from Interface gi0/1 VLAN was displayed with VLAN-ID 100 while on port gi0/2 VLAN-Id 1 was recognized. Can you double-check if all VLAN 100 addresses are bind to gi0/1? As the Interface gi0/1 is "Access" the VLAN Id 100 is added by the Interface when an end device (PC?) sends untagged Frames. I would recommend to check the vlan configuration in the next step. Can be find also in running-config.

[jakkrit01]

Hi  Krishan,

Thank you for your point, now I saw a root cause of this problem, because on a firewall connect via Gi0/1 broadcast subnet 172.X.X.X back to switch 2960X, now I'm edit configuration on firewall and ARP table back to normal