How to configure listener and tns

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Oracle

TOAD

Scenario:
I have a Server called A having two IP: IP1 & IP2 with hostname HsN.
Now I have two client Windows xp(C1) and windows server2003(C2) from where I want to access DB from toad.
C1 successfully ping to IP1 and also server A listener & tns details is with IP1
whether C2 can ping to IP2 and can only be connect when direct connect(in toad) with hostname HsN with dynamic port(when server restart i have to change port everytime)
Also, If I changed listener/tns details with HsN instead of IP1 account gets locked.

how do I configure all, so that C1 & C2 both will be able to connect to server using toad?

urgent help needed to resolve.

What I have tried:

I tried to create new listener but error is:

listener does not currently know of sid

when i changed existing listener & tns with hostname instead of IP, error is:

Account is locked