Is there a certain range of IP addresses that a host can obtain? for example is it possible for a host to obtain IP Address 255.255.255.255 or 0.0.0.0 or 1.2.3.4 or something like that? thanks. skud. This message was edited by skud, on 5/28/2001 3:55:20 PM
Posted on 2001-05-28 15:53:00 by skud
Even if the OS lets you assign any IP address, certain IP addresses have a special meaning (for example 255.255.255.255 is the broadcast address). If your machine is connected to a network, using a special adress or an adress that has already been assigned will cause trouble in the network. But I don't know if the OS will prevent you from assigning an IP adress. You will have to test on different OSes.
Posted on 2001-05-29 17:11:00 by karim
I'm not sure of the question you are really asking. Yes there are rules... 0.0.0.0 isn't available (illegal as address, all 0's ) has special meaning to Cisco routers 1.2.3.4 probably exists but is unreachable by me 255.255.255.255 (illegal as address, all 1's ) reserved for broadcast

There are five classes, A thru E of network addresses.

Class A, leading bit pattern of the first byte 0, dec range 1-127, max networks 127,
nodes per network 16,777,214 , default mask 255.0.0.0  

Class B, leading bit pattern pattern of the first byte 10, dec range 128-191, max networks 16,834,
nodes per network 65,534 , default mask 255.255.0.0

Class C, leading bit pattern pattern of the first byte 110, dec range 192-223, max networks 2,097,152,
nodes per network 254 , default mask 255.255.255.0

Class D 224.0.0.0 - 239.255.255.255 for multicast
Class E 240.0.0.0 - 255.255.255.255 reserved

The mask determines what portion of the IP is the Network address and which portion the host, and or nodes.

For example below, a class A address, using a default mask, the network portion is 12, leaving 16,777,214 possible hosts

 12. 16.135. 14 bin IP   00001100.00010000.10000111.00001110
255.  0.  0.  0 Bin mask 11111111.00000000.00000000.00000000


There are some addresses in the 19x.xxx.xxx.xxx range that are considered private, and won't be passed/forwarded thru a router.

This message was edited by SFinegan, on 5/31/2001 12:36:40 AM
Posted on 2001-05-29 19:49:00 by SFinegan

 Karim is correct.

 skud, the first two group of each IP address is very important.

 (255).(255).255.255    those first two group are the country code.

 for example: 127 <----- located in U.S.A
              207 <----- located in Canada
 and so on. 127 is not just 127, it goes with a combination
 of the second number 255.x. <---

 as you no doubt have guessed, that's what ip attacker try
 to look for when... well, you know what i'm talking about.
 ;)

 note: correct me if i'm wrong (i mean it)

This message was edited by disease_2000, on 5/30/2001 10:58:32 PM
Posted on 2001-05-30 22:55:00 by disease_2000
Disease2000 Sorry, you are wrong. I'm still waiting to find out what skud really wants to know so that I can give a more complete answer (without doing a complete tutorial). Scott
Posted on 2001-05-30 23:46:00 by SFinegan
I live in canada and my ip starts with 24
Posted on 2001-05-31 02:21:00 by Satrukaan

 thanx for correcting. i once read an article on IP address and
 that's what i learned.

Posted on 2001-05-31 02:24:00 by disease_2000
-scott sorry if im not so clear about what i mean sometimes. what i mean is if i wanted to scan a range of ip addresses on a certain port, say 80, to see which have an http server running. then what range of ip addresses would i need to scan to retrieve a complete list. if i was to scan from 0.0.0.0 to 255.255.255.255 then it will take a very long time (10,000,000,000,000 possible ip addresses :) thanx. skud. This message was edited by skud, on 6/2/2001 6:10:05 PM
Posted on 2001-06-02 18:07:00 by skud

 skud,

 check out: http://www.yale.edu/pclt/COMM/TCPIP.HTM
            http://www.private.org.il/tcpip_rl.html
            http://www.cisco.com/warp/public/105/index.shtml
            http://www.microsoft.com/technet/network/ipvers6.asp
 ==========================================================
 skud, it's not a good idea to scan ip from 0 to x (where x
 is the limit).

 some university own a certain number (the first two group)
 some country own certain number and so on... know what yo-
 u're doing and life will be easy for you in this area...
This message was edited by disease_2000, on 6/2/2001 6:36:16 PM
Posted on 2001-06-02 18:28:00 by disease_2000

Yes there are a lot of addresses.

For example below, a class A address, using a default mask,
the network portion is 12, leaving 16,777,214 possible hosts/nodes/users

 12. 16.135. 14 bin IP   00001100.00010000.10000111.00001110
255.  0.  0.  0 Bin mask 11111111.00000000.00000000.00000000

Using the example above, the first octet is 12, the Network portion. 
You would scan from 12. 0. 0 . 1  to 12.255.255.254 before
incrementing to 13.

When you get to 128 the default Mask automatically changes to
255,255. 0. 0 so you would scan 128. 0. 0. 1 to 128. 0. 255.254
before incrementing to 128. 1. 0. 1

Think of the Network portion of the address as the piece of cable bounded by routers. The IPs/nodes attached to the cableare on the same network address. You can contact any IP on yourcable directly, anything with a different Network portion address is passed through a router (different from a Hub or Repeater). disease2000 One of the reasons the US has more lower numbers is that the Net started here and expanded outward to other countries. The Network portion can be reassigned by the controling body. I had to read many different explanations of IP addressing and subnetting before I got a clue. If you don'tunderstand something, find another source and try again. I did not go into subnetting because it would take me fifteen or so pages to try to explain it (I make a lousy teacher). skud It appears that you need to learn about subnetting also. Subnetting gets confusing because we borrow bits from the Network portion of the address to get more nodes, however the numbers don't run consecutively. Check the Cisco site disease2000 posted. This message was edited by SFinegan, on 6/3/2001 1:17:51 PM
Posted on 2001-06-03 13:05:00 by SFinegan
1.2.3.4 is part of subnet NET-RESERVED-1, which belongs to the Internet Assigned Numbers Authority (IANA). I got this from a IP / Subnet reference called the The IP Address Bible, released by "Da Cyber Syndicate". The URL mentioned in the doc no longer exists, but you can always search for it or I can mail it to you if you're interested.
Posted on 2001-06-03 13:46:00 by Qweerdy