[Ham-Computers] RE: Access question

[Marcel Buijs]

Gene, the option with the Mac adress is a good option, but you have know
more about Network tecnics.

Using Static IP and a firewall is also an option.

You only have to grant the PC, and block the Xbox Nic.

Marcel Pe1nms

-----Oorspronkelijk bericht-----
Van: ham-computers-bounces at mailman.qth.net
[mailto:ham-computers-bounces at mailman.qth.net]Namens Hsu, Aaron (NBC
Universal)
Verzonden: donderdag 3 februari 2005 1:42
Aan: 'I>Ham-Computers'
CC: 'erastber at tampabay.rr.com'
Onderwerp: [Ham-Computers] RE: Access question


Gene,

In short, here are two options I can think of...

1.  Filter by MAC address rather than IP address.  This will filter by the
physical address burned-in to the NIC...something not that easily
changeable.

2.  Use Static IP addressing.To recap, you have two choices...

This get's long, so those interested can read on...if you're not interested,
press the delete key now <g>.


Filtering by MAC address
------------------------
Rather than filter by IP addresses, setup the router to filter by MAC
address.  No, this is not a "Macintosh" address - it's a "Media Access
Control" address.  Each NIC (Network Interface Card, aka a network card)
manufacturer has a registered "prefix" 3-bytes long and a 3-byte "counter"
or serial number.  This makes a 6-byte (48-bit) MAC address that is
physically burned-in to every network card and is used to uniquely identify
a NIC on any particular network.  Theoretically, no one network should have
two NIC's with the same MAC address (as this would cause some problems).

Anyways, the Linksys router should have a config page to filter by MAC
address.  On Win2K/XP systems, you can determine your NIC's MAC address by
going to a COMMAND PROMPT and typing the following:

  ipconfig /all

You may get a listing for more than one NIC if you have that many installed.
You'll see in the list "Physical Address" followed by "xx-xx-xx-xx-xx-xx".
The "xx" number is the MAC address of your NIC.  Enter this number into the
MAC filter page on the router and that should do it.  I don't know if the
Linksys MAC filters are "Allow" or "Block", so make sure you type in the MAC
addresses accordingly.

For example, if your router "allows" filtered MAC addresses and your
computer's MAC address is 00-11-22-33-44-55, then enter this number on the
router's MAC filter configuration page.  Do the same for every other
computer you want to "allow" access to the internet.

If the router "blocks" filtered MAC addresses, then you'll need to enter the
MAC address of the Xbox so it is "blocked".


Using Static IP addressing
--------------------------
Now if your router doesn't allow filtering by MAC address on a schedule
(which may be the case), then the best thing you can do is to assign static
IP addresses to all the devices on your network.  For simplicity, most
routers and computers are set to use DHCP, a dynamically assigned IP
address.  Basically, computers broadcast (yell) on the wire a request for an
IP address.  A DHCP server (your router) hears the request and sends your
computer an IP address.  OTOH, when using static IP addresses, you manually
assign an IP address to the devices on your network.

By default, Linksys routers are usually set to 192.168.1.1.  To make it
simple, you will want to configure your computers/Xbox with 192.168.1.x IP
addresses (different "x" for each machine - e.g. 2, 3, 4, 10, etc.).  You
will also need to enter a network mask and a gateway address.  In your
situation, the mask will be 255.255.255.0 and the gateway is the IP address
of the router (192.168.1.1).  One last thing you'll need to do is enter a
DNS server address.  The Linksys routers usually do DNS forwarding, so you
can enter the router's address as the DNS server (192.168.1.1).  Then setup
your filter page to filter the Xbox's IP address.  Sorry, I don't have an
Xbox, so I can't show you how to set it for such...check the manual(s) or do
a Google search for "Xbox static ip".  Here's the basic info:

To briefly recap:

  Computer/Xbox IP addresses: 192.168.1.x
  Subnet Mask: 255.255.255.0
  Gateway: 192.168.1.1 (or the address of your router)
  DNS Server: 192.168.1.1 (or the address of your router)

If you know it, enter your ISP's DNS server address as an "alternate" DNS
entry.  This will make sure that if something happens where the router isn't
responding to DNS requests, the alternate DNS server will be tried.  You'll
need to find out from your ISP what DNS server to use (or the info may be
available on the "WAN" configuration page of the router.

So, for example, use 192.168.1.2 for your computer, 192.168.1.3 for your
son's computer, 192.168.1.4 for the Xbox.  Set your filter to block
192.168.1.4 and it will block the Xbox from the internet.  Better yet, if
you can set the filter to "Allow", then only "allow" your computers access
during the scheduled time by entering their IP addresses in the filter
configuration page.

Of course, if your son is smart enough, he can just change the IP address to
something different that's not blocked.  That's why MAC address filtering is
preferred...harder to change (and may not be possible with some NIC's).

And, as someone else mentioned, this may not really be a "block or allow"
issue on the router...it may be a dicipline issue - but each family handles
things differently, so I won't go here.  <g>


This got into a bit of detail, so please let me know if you have any Q's.

73,

  - Aaron Hsu, NN6O (ex-KD6DAE)
    {nn6o}@arrl.net
    {athsu}@nbcuni.com
    No-QRO Int'l #1,000,006
    . -..- - .-. .-   ".... . .- ...- -.--"
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