what is the purpose of switch cmd ip tacacs source-interface vlan X

[adeebtaqui]

what is the purpose of switch cmd "ip tacacs source-interface vlan X(mgmt)"?  Is it a must to configure or more secure ?

[DanielP211]

To source the tacacs traffic from a specific interface/vlan (in case you have more).

[Flavio Miranda]

Hi @adeebtaqui 

 It is not a must. And it is more secure in the sense that you can have a better control on from where you send the tacacs request. But keep in mind that if you change the source for tacacs you must update the tacacs server, otherwise you can be locked out from the device.

[MHM Cisco World]

Not mandatory to config 

BUT case you  need it 

If there is FW and FW allow one IP through acl and nat here you need to specify mgmt IP 

Many many cases I see' the sw is l2 not l3 so there is defualt gw and no ip routing' and default gw is reachable via only mgmt subnet' here mandatory you need to specify mgmt IP as source to connect server

[Joseph W. Doherty]

Without it, the tacacs server, I recall, will see the IP of the device's L3 egress interface which might differ if there are different possible paths between devices.