Re: Fixed IP / IP ranges

["kinchyuk" <alex@xxxxxxx>]

It's to do with classless IP routing (CIDR, or classless inter-domain
routing to give it's full title), and generally indicates the number
of IP addresses in a subnet. /29 will give you 6 useable IPs once
you've taken away two for network address and broadcast address. A /8
is rather larger, with 16,777,214 useable IPs after the above
subtractions.

Have a look at http://johnno.casebook.org/subnet.html
for a table of
these sort of things, or
http://www.urec.cnrs.fr/autres_techno/BGP4/CIDR_faq.html
for a CIDR
FAQ.

HTH,

Alex

--- In ukha_d@xxxxxxx, <mailinglists@v...> wrote:
> Gerard,
>
> My TCP/IP knowledge is a bit thin, what does the /29 and /8 mean?
>
> Cheers,
> Lee
>   -----Original Message-----
>   From: Gerard McGovern [mailto:stuff@xxxxxxx...]
>   Sent: 10 July 2003 14:53
>   To: ukha_d@xxxxxxx
>   Subject: RE: [ukha_d] Fixed IP / IP ranges
>
>
>   > Yeh well said.... and if I may add why the hell the need for
>   > a /29 (7 ips @ home on an adsl connection). You can't do any
>   > serious serving at home anyway. Come on folks there aint that
>   > many ipv4 addresses around so this is just a waste.
>
>   Actually I read an article that suggested if IPs were allocated
properly
>   then we'd be fine for quite some time. I'll copy and paste this
>from
>   article I found:
>
>   "It's being deliberately created by groups with financial
interests in a
>   move to IPv6. Check out webpage...
>   http://www.iana.org/assignments/ipv4-address-space
for some real
> stupidity.
>   The following all have 16 million public IP addresses, except HP
which has
>   32 million. We're talking a grand total of over 240,000,000, yes
folks
> *TWO
>   HUNDRED AND FORTY MILLION PUBLIC IP ADDRESSES* assigned to
outfits that
>   don't really need them (see below). Then there are companies
where every
>   desktop has a public address. This is not only wasteful, but
stupid
>   security-wise. You do *NOT* want your desktops accessable from
outside.
> NAT
>   lets them surf the net, thank you. Furthermore, discussions in
anti-spam
>   groups indicate that *ASSIGNED* address ranges that belong to
bankrupt
>   companies have been hi-jacked by spammers, because nobody's
around to
> claim
>   the addresses. The so-called shortage is a joke. The only
question in my
>   mind is whether this is incompetence or deliberate waste in an
effort to
>   force IPv6 before it's really necessary.
>
>   General Electric has 16 million addresses (3.0.0.0/8) even though
it has a
>   policy of *NOT* routing them externally. GE goes and gets other
address
>   ranges for its external-facing servers. Sheesh.
>
>   Xerox (13.0.0.0/8)
>
>   HP started out with 16 million (15.0.0.0/8) and acquired Compaq
which had
>   acquired Digital and its 16 million (16.0.0.0/8). HP now has
*THIRTY-TWO
>   MILLION* public IP addresses.
>
>   Apple (17.0.0.0/8)
>
>   MIT (18.0.0.0/8)
>
>   Ford (19.0.0.0/8)
>
>   Halliburton (34.0.0.0/8)
>
>   Eli Lily (40.0.0.0/8)
>
>   Bell-Northern (47.0.0.0/8)
>
>   Prudential Securities (48.0.0.0/8)
>
>   Department of Social Security UK (51.0.0.0/8)
>
>   Dupont (52.0.0.0/8)
>
>   Merck (54.0.0.0/8)
>
>   USPS (56.0.0.0/8)"
>
>   G
>
>   --
>
>
> [Non-text portions of this message have been removed]