Router and LAN configuration


I have ( probably ) a silly question

I want to change our router and I want to use a LAN network/subnet of Class A

Let's suppose, that I setup a machine on my LAN with the IP address of ( that the IP address of google on the Net !!! )

- How the system will make the difference between a machine on my LAN and a machine on the Internet ?????

- Does it mean, that Class A network are prohibited for "private" LAN ?

- is there any specific configuration for such LAN network ?

What do you think ?


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If that Class A address block does not belong to you, you CANNOT connect to the Internet with it. But you can use a private IP Class A address block (see RFC 1918), and then connect a NAT between your net and the Internet.

I'm pretty sure that the IANA is NOT assigning anyone Class A nets anymore.


Reply to
Albert Manfredi

Albert Manfredi wrote: (snip)

Well, behind a properly configured NAT router no-one outside should notice, though people inside won't be able to reach outside hosts on that net.

There is available net 10 in the private addresses, a fine class A net. Everyone I know using net 10 subnets it at /24, though technically it is still a class A net.

But maybe subnets of them?

I believe Comcast has 24, 65 and 76, but I don't know when they got those. Also, at least mine is on a /21 subnet. (Do they really put that many hosts on a single subnet?)

Also, this should go to comp.dcom.protocols.tcp-ip.

-- glen

Reply to
glen herrmannsfeldt

Seeing as how most networking people dropped "Class" A, B, C, D and E designations after RFC1517, RFC1518 and RFC1519 came out over 16 years ago... never mind that IANA isn't assigning blocks to anyone other than the five Regional Internet Registries (AfriNIC, APNIC, ARIN, LACNIC and RIPE), yeah that's reasonable.

If you look at recent allocation data, the five RIR have become a lot tighter handing out chunks of IPv4 space. I don't have actual stats handy, but the visual impression of viewing the monthly differences show a lot more new blocks at and below a /20, with a high incidence of /24s (former 'Class C') chunks.

Never - they don't have those /8s. is assigned/allocated to more than 10 different companies in six countries (.ar, .bs, .ca, .nl, .pr and .us). is assigned/allocated to more than a dozen companies and seven countries (.bb, .bs, .ca, .jm, .pr, .tc and .us). is similarly fragmented, but only five countries (.ag, .bm, .ca, .pr and .us). The URL

formatting link
might be useful.

Technology. Try "what is a switch" compared to "what is a hub". Same concepts.

Old guy

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