Thanks a lot
I will try to do what you suggest tomorrow (now I'm at home)
Because I'm not sure how to deal with the matter. I read something related to "ROUTE" and "NAT" and from that I thought it can help.When I use "ROUTE", the ip addresses will not be hidden by the gateway. Thus, I tried "ROUTE", however, the computer 192.168.1.6 can't ping any computer in the network 192.168.123.0
Thanks sec_ware, I'll do what you suggest tomorrow