Edit or create /etc/xinet.d/yourservicename

E.g. to listen to 443 and redirect to 192.168.2.1 port 22, replace listenport = 443, targetip = 192.168.2.1, targetport = 22.

service yourservicename
{
        disable         = no
        type            = UNLISTED
        socket_type     = stream
        protocol        = tcp
        user            = nobody
        wait            = no
        redirect        = targetip targetport
        port            = listenport
}