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Cable Internet Access

 It seems to be a long ago.
Once, Mushashino Mitaka Cable Television was one of ISPs. I use.

There are three types of services they provide. I use IP assigned LAN type service. The network configuration is almost the same as you access to the network with IP address assigned from the DHCP server. This service is not cheap and character charged. But you can enjoy much more wider bandwidth than ISDN.

When you want to access the Internet from every PC on your HomeLAN, there is a problem. You can register just one MAC address to the provider. This is because they need to know whcih IP address is assigned to which MAC address when they try to trouble shoot. But still not convenient for me.

 You can find many cheap ISDN routers, but they cannot handle this type of connection.

So, I tried to configure a sort of Gateway that's NICon the outer segment has a registered MAC address. It must work as NAT which translate my HomeLAN's private IP address to the assigned IP address.

I decided to use Linux based IP Masquerade on old 486DX2 50MHz PC. I installed dhcpcd as DHCP client software.

The biggest challenge was to make 3Com's 3C509B NIC recognized by Linux. I had to "make" the kernel. It took almost 6 hours. And IRQ and I/O address setting was also troublesome. 3Com's Install FD's setting was not accepted by Linux. Linux accepted settings that Windows95 P&P set.

The ISP assigns a private class B IP address to each machine. So, your machine cannot be accessed from the outside (The Internet). I'm not happy with this. I could do many things if my machine assigned global IP address.

Anyway, my PCs in the bedroom on the 2nd floor can access the Internet thru this gateway PC on the 1st floor. This line is much faster than the company I'm working for.


LAN Configuration


LANcity's Cable MODEM
traceroute command to IIJ.
Parkcity is connected with Tokyo Internet at Mitaka AP.
Login page on Gateway2000 Liberty(486DX4-100) on the 2nd floor.
You must to type in your user name and password to be connected.