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There are a number of lists on the web that define all valid public ip addresses ranges but they don't seem to be very accurate.

The most common list Ive found is show below. This list however doesn't include addresses in 191.236.x.x even though there are public web servers in that range.

Is there a definitive and correct list?

  • 1.0.0.0 - 9.255.255.255
  • 11.0.0.0 - 126.255.255.255
  • 129.0.0.0 - 169.253.255.255
  • 169.255.0.0 - 172.15.255.255
  • 172.32.0.0 - 191.0.1.255
  • 192.0.3.0 - 192.88.98.255
  • 192.88.100.0 - 192.167.255.255
  • 192.169.0.0 - 198.17.255.255
  • 198.20.0.0 - 223.255.255.255
PeterJ
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4 Answers4

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IANA provides standards on this subject. For IPv4, here is what they have in their "special purpose address registry". Meaning, for our purposes, anything in these address blocks shouldn't be assigned because they shouldn't be routable "publicly".

0.0.0.0/8
10.0.0.0/8
100.64.0.0/10
127.0.0.0/8
169.254.0.0/16
172.16.0.0/12
192.0.0.0/24
192.0.0.0/29
192.0.0.8/32
192.0.0.9/32
192.0.0.170/32
192.0.0.171/32
192.0.2.0/24
192.31.196.0/24
192.52.193.0/24
192.88.99.0/24
192.168.0.0/16
192.175.48.0/24
198.18.0.0/15
198.51.100.0/24
203.0.113.0/24
240.0.0.0/4
255.255.255.255/32

# Also to be considered, multicast addresses subnet:
224.0.0.0/4

This is more consistent with the example you provided above.

If you don't understand CIDR notation, you can convert them to ranges here.

Gohu
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BrianC
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  • You forgot the multicast addresses, which, from a practical perspective, cannot be used on the Internet. `224.0.0.0/4`. – Ron Maupin Mar 17 '16 at 00:27
  • @RonMaupin That's true, thanks. I added that (as well as 239.0.0.0/8) to my post. – BrianC Mar 17 '16 at 00:42
  • Also, there are IPv4 bogon lists which many ISPs use to block addresses from being routed on the Internet, e.g. http://www.team-cymru.org/Services/Bogons/fullbogons-ipv4.txt "_A bogon prefix is a route that should never appear in the Internet routing table. A packet routed over the public Internet (not including over VPNs or other tunnels) should never have a source address in a bogon range._" – Ron Maupin Mar 17 '16 at 00:46
  • Well...I guess it really boils down to whether or not you consider valid "public" ranges to be not assigned, or not reserved. – BrianC Mar 17 '16 at 00:50
  • Well, from a practical perspective, if the carriers won't route to or from those addresses, are they really valid public addresses? I guess it's where you come down on that. – Ron Maupin Mar 17 '16 at 00:51
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    Thanks for the response but the point of question was to provide a reference for the valid ranges not the exclusions – PeterJ Mar 24 '16 at 21:49
  • @PeterJ Did you ever find an answer to your original question? I too am looking for the answer. – fire_water Aug 04 '17 at 01:02
  • @PeterJ: Valid ranges are simply "everything _minus_ the exclusions". They are not explicitly documented anywhere, because such a list can be _easily computed_ from an exclusion list – so there is no sense in maintaining it separately. When IANA says "these ranges aren't public", they sometimes even explicitly state that "everything else _is_ public" (at least they do for IPv6). – u1686_grawity Sep 19 '18 at 18:42
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    In the context of this question it doesn't make sense to list nets 192.0.0.0 with a bigger netmask than 24 here, because they are included in 192.0.0.0/24. The IANA list assignes special names for these subnets, so it makes sense there. But here it's just a list. – David Ongaro Mar 19 '19 at 16:40
  • @grawity - I love comments like this. This is why you get gags like... how many IT guys does it take to change a light bulb. The next time you are in an exam and the question states how many usable IP addresses in a /24 subnet, see if they mark you correctly if your answer is - 255 minus the unusable ones. Answer the question, don't query the person on how i why they want the information. – PeterJ Jun 21 '19 at 00:46
3
  • 1.0.0.0-9.255.255.255
  • 11.0.0.0-100.63.255.255
  • 100.128.0.0-126.255.255.255
  • 128.0.0.0-169.253.255.255
  • 169.255.0.0-172.15.255.255
  • 172.32.0.0-191.255.255.255
  • 192.0.1.0/24
  • 192.0.3.0-192.88.98.255
  • 192.88.100.0-192.167.255.255
  • 192.169.0.0-198.17.255.255
  • 198.20.0.0-198.51.99.255
  • 198.51.101.0-203.0.112.255
  • 203.0.114.0-223.255.255.255
Scott - Слава Україні
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hmuller
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0

Combining the lists from BrianC and hmuller I figured that 3 ranges do overlap:

  • 192.31.196.0/24
  • 192.52.193.0/24
  • 192.175.48.0/24

In my combined list, they are considered as not valid:

CIDR             First IP      Last IP          
0.0.0.0/8        0.0.0.0       0.255.255.255    Not valid
                 1.0.0.0       9.255.255.255    Valid
10.0.0.0/8       10.0.0.0      10.255.255.255   Not valid
                 11.0.0.0      100.63.255.255   Valid
100.64.0.0/10    100.64.0.0    100.127.255.255  Not valid
                 100.128.0.0   126.255.255.255  Valid
127.0.0.0/8      127.0.0.0     127.255.255.255  Not valid
                 128.0.0.0     169.253.255.255  Valid
169.254.0.0/16   169.254.0.0   169.254.255.255  Not valid
                 169.255.0.0   172.15.255.255   Valid
172.16.0.0/12    172.16.0.0    172.31.255.255   Not valid
                 172.32.0.0    191.255.255.255  Valid
192.0.0.0/24     192.0.0.0     192.0.0.255      Not valid
192.0.1.0/24     192.0.1.0     192.0.1.255      Valid
192.0.2.0/24     192.0.2.0     192.0.2.255      Not valid
                 192.0.3.0     192.31.195.255   Valid
192.31.196.0/24  192.31.196.0  192.31.196.255   Not valid
                 192.31.197.0  192.52.192.255   Valid
192.52.193.0/24  192.52.193.0  192.52.193.255   Not valid
                 192.52.194.0  192.88.98.255    Valid
192.88.99.0/24   192.88.99.0   192.88.99.255    Not valid
                 192.88.100.0  192.167.255.255  Valid
192.168.0.0/16   192.168.0.0   192.168.255.255  Not valid
                 192.169.0.0   192.175.47.255   Valid
192.175.48.0/24  192.175.48.0  192.175.48.255   Not valid
                 192.175.49.0  198.17.255.255   Valid
198.18.0.0/15    198.18.0.0    198.19.255.255   Not valid
                 198.20.0.0    198.51.99.255    Valid
198.51.100.0/24  198.51.100.0  198.51.100.255   Not valid
                 198.51.101.0  203.0.112.255    Valid
203.0.113.0/24   203.0.113.0   203.0.113.255    Not valid
                 203.0.114.0   223.255.255.255  Valid
224.0.0.0/4      224.0.0.0     239.255.255.255  Not valid
240.0.0.0/4      240.0.0.0     255.255.255.255  Not valid
Den
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-1

All IP address from 1 to 191 excluding the RFC1918 private addresses below are assigned for Public IPs.:

RFC1918 - Private address alocation:

  • 10.0.0.0 - 10.255.255.255 (10/8 prefix)
  • 172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
  • 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)
tripleee
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Muhammad Riaz
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    Not all of them. (100.64.0.0/10 for example?) And the public allocations don't end at 191, they continue all the way to 223. – u1686_grawity Sep 19 '18 at 14:29