# Are IP addresses intelligent? **URL:** \ **Category:** Factual Questions\ **Created:** [June 13, 2000, 3:22pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238 "2000-06-13T15:22:56Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [June 13, 2000, 3:22pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/1 "2000-06-13T15:22:56Z")
Like phone numbers. Phone numbers are sorta intelligent. Some parts mean something, and some don’t. How about IP’s? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 13, 2000, 3:33pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/2 "2000-06-13T15:33:53Z")
Nope…there is no rhyme or reason to IP addresses. Certain addresses are ‘restricted’ as internal only addresses but otherwise you can tell nothing about where a computer ‘is’ by looking at its address. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [June 13, 2000, 4:12pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/3 "2000-06-13T16:12:15Z")
Well, there are some patterns. A company can own a large block of IP addresses. For example, any IP that starts with 15.xxx.xxx.xxx is in the [hp.com](http://hp.com) domain. 206 and 207 belong to AOL, IIRC. You can tell what domain a computer is in by looking at its IP address. ---
**Author:** ![Bricker](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@Bricker](https://boards.straightdope.com/u/Bricker)\ **Post date:** [June 13, 2000, 5:41pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/4 "2000-06-13T17:41:34Z")
It depends on what you mean by “mean something.” If my phone number is (703) 573-2687, for example, we may safely conclude that I live in Northern Virginia (the 703 area code) and the Fairfax/Falls Church area (the 573 exchange). The 2687 is meaningless. Now, if I have a computer with a host IP address of 198.14.17.5, we may also safely conclude some things. This is a Class C address, which means that my network probably has no more than 254 hosts, and my network number is 198.14.17.0. We can look up the registration for the network number, and discover what company ‘owns’ that network. However, it may not be that useful. For example, if I’m a dial-up user from home, as so many people are, it’s likely that I’ll be assigned a new address every time I call. So discovering my IP address in that circumstance will tell you only who my ISP is, not who I am, or where I live. My real-life ISP is [erols.com](http://erols.com), which has points-of-presence in many diffreent areas, so getting the fact that I use Erol’s would not even help you discover what state I lived in. For network engineers, the IP address and subnet mask, in the context of the known network, can provide plenty of useful information. A company may subnet its internal network and use static IP addresses, so that a troubleshooter could see 198.14.17.5 and instantly know it’s on the first floor, while 198.14.17.249 is on the fourth floor. But an IP address alone, devoid of any context, is not tremedously useful. - Rick ---
**Author:** ![soulsling](https://avatars.discourse-cdn.com/v4/letter/s/a5b964/32.png) [@soulsling](https://boards.straightdope.com/u/soulsling)\ **Post date:** [June 13, 2000, 5:45pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/5 "2000-06-13T17:45:40Z")
thank you **Bricker** , well said 🙂 ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [June 13, 2000, 6:02pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/6 "2000-06-13T18:02:11Z")
\>\> Are IP addresses intelligent? Compared to what? ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [June 13, 2000, 7:16pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/7 "2000-06-13T19:16:48Z")
> [@](#): > > \>\> Are IP addresses intelligent? > > Compared to what? Compared to IQ addresses, of course. It’s only one letter off, after all. ---
**Author:** ![eggo](https://avatars.discourse-cdn.com/v4/letter/e/c4cdca/32.png) [@eggo](https://boards.straightdope.com/u/eggo)\ **Post date:** [June 13, 2000, 10:12pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/8 "2000-06-13T22:12:16Z")
> [@](#): > > Well, there are some patterns. A company can own a large block of IP addresses. For example, any IP that starts with 15.xxx.xxx.xxx is in the [hp.com](http://hp.com) domain. 206 and 207 belong to AOL, IIRC. You can tell what domain a computer is in by looking at its IP address. also, any ip begining with 24 is a cable modem subscriber (i.e.: 24.xxx.xxx.xxx) ---
**Author:** ![handy](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@handy](https://boards.straightdope.com/u/handy)\ **Post date:** [June 13, 2000, 11:36pm UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/9 "2000-06-13T23:36:40Z")
I use IP’s to graph the visitors on my web site. It gives the country they are from about 80% of the time. Very useful & can tell me where they are going on the web site, how long they stay & what they are doing. Average visit used to be about 7.5 minutes but is around 6 minutes now. ---
**Author:** ![billehunt](https://avatars.discourse-cdn.com/v4/letter/b/c37758/32.png) [@billehunt](https://boards.straightdope.com/u/billehunt)\ **Post date:** [June 14, 2000, 5:39am UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/10 "2000-06-14T05:39:34Z")
**Bricker** is mostly right. However, nowadays, class addresses are rarely given out entirely. Instead, they are broken into smaller CIDR blocks. For example, (this is not a real situation, just an example), in **Brickers** IP address 198.14.17.5, it’s possible that the class C block 198.14.17.0 is broken into two blocks of 127 addresses, 198.14.17.0 and 198.14.17.128, each with mask 255.255.255.128. Each of these two blocks could be owned by different companies, potentially on opposite sides of the planet. (It’s actually more likely that they’ll be geographically close, since the Class C really belongs to the two companies common ISP, and there are reasons to keep the Class C within a single router, but conceivably they could be very distant.) Another minor nit: A class C is used to provide 254 addresses as **Bricker** notes, but the .0 address isn’t really reserved and nowadays you’ll see more and more of these in use, meaning 255 addresses can be used. The .255 address can’t be used of course, since that’s reserved for broadcast. ---
**Author:** ![billehunt](https://avatars.discourse-cdn.com/v4/letter/b/c37758/32.png) [@billehunt](https://boards.straightdope.com/u/billehunt)\ **Post date:** [June 14, 2000, 5:42am UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/11 "2000-06-14T05:42:25Z")
That last paragraph should begin “A class C used to provide…” ---
**Author:** ![waterj2](https://avatars.discourse-cdn.com/v4/letter/w/858c86/32.png) [@waterj2](https://boards.straightdope.com/u/waterj2)\ **Post date:** [June 14, 2000, 6:02am UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/12 "2000-06-14T06:02:40Z")
How can you tell that it’s a class C? The college I go to owns a class B (128.113.0.0). Is there any way to tell that this is what they own from the IP address (say 128.113.113.33, one of their telnet servers)? One place to check is [http://www.arin.net/whois/](http://www.arin.net/whois/) which would tell you [this](http://www.arin.net/cgi-bin/whois.pl?queryinput=128.113.113.33). Using tracert in DOS, you can see that this is in the Albany area, as it goes through a router called [at-gw3-alb-0-0.appliedtheory.net](http://at-gw3-alb-0-0.appliedtheory.net) right before going through a router on campus. Of course Applied Theory (the school’s ISP) is under no obligation to label their routers geographically, but they seem to. ---
**Author:** ![billehunt](https://avatars.discourse-cdn.com/v4/letter/b/c37758/32.png) [@billehunt](https://boards.straightdope.com/u/billehunt)\ **Post date:** [June 14, 2000, 6:34am UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/13 "2000-06-14T06:34:54Z")
**waterj2** wrote > [@](#): > > How can you tell that it’s a class C? Look at the first octet: A 0 - 127 B 128 - 191 C 192 - 223 D 224 - 239 (Multicast) E 240 - 255 (Experimental) Note that all addresses of individual hosts will be either A, B, or C. You will never see so-called non-routable addresses (per RFC 1918, I think): A 10.0.0.0 - 10.255.255.255 B 172.16.0.0 - 172.31.255.255 C 192.168.0.0 - 192.168.255.255 ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [June 14, 2000, 6:41am UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/14 "2000-06-14T06:41:19Z")
> [@](#): > > \*\* > How can you tell that it’s a class C? > \*\* It depends on the bits in the network number. A class A address has an 8 bit network number and 24 bit host number, and the high-order bit of the network number must be zero. Therefore, addresses whose first byte is between zero (00000000) and 127 (01111111) are class A addresses, giving 127 possible class A’s, each with 2^24 = 16,777,216 hosts. A class B has a 16 bit network number and 16 bit host number, and the network number must begin with 10. Thus, everything from 128.0.x.x (10000000.00000000.x.x) to 191.255.x.x (10111111.11111111.x.x) is a class B network - giving 16,384 possible class B’s, each with 16,384 hosts. Class C networks have a 24 bit network number and an 8 bit host number, and the network number must begin with 110. So everything from 192.0.0.x (11000000.00000000.00000000.x) to 223.255.255.x (11011111.11111111.11111111.x) is a class C network, making 2,097,152 class C networks (2^21). Of course, you don’t really have all the networks and hosts in a possible range. 127.0.0.x is reserved for loopback devices, the “all ones” host on a given network is the broadcast address. (broadcast = all hosts on network). 0.0.0.0 is the default route, etc, etc, etc. ---
**Author:** ![GaWd](https://avatars.discourse-cdn.com/v4/letter/g/f08c70/32.png) [@GaWd](https://boards.straightdope.com/u/GaWd)\ **Post date:** [June 14, 2000, 10:46am UTC](https://boards.straightdope.com/t/are-ip-addresses-intelligent/22238/15 "2000-06-14T10:46:36Z")
I think you might almost be able to consider the lil buggers “intelligent” to a certain extent that some numbers(10.10.XX.XX), may not be routed. Besides classes, IP numbers aren’t intelligent. They might tell you what company owns them, but that doesn’t mean squat, except for it’s probable origin. -Sam