No... There Are Only For Broadband Sharing... Not For A Dial-up Connection
Really? The guide mentions dial up explicitly, and broadband not at all (AFAICT).
Nevertheless, please paste the following information for both of your machines:
$ ip route
$ iptables -t TABLE -nL
(replace TABLE with each of nat, filter, mangle, raw)
(this is probably called something different of red hat linucies; post the configuration of your network interfaces)
Which steps of the guide did you perform? Did any of them fail?
One thought: if your ISP lets you connect more than one machine, you can also bridge the two networks instead. That effectively turns the one connected to your ISP into a switch for the other one, so that it gets dhcp information from the ISP and you don't need to set up dhcp/dns/routing configuration yourself. I'd probably go with this unless you want the ISP-facing box to also act as a firewall [and even so, you can use ebtables]. Search the web for a good bridging guide