How many IP addresses are there in China?

The topic we are going to talk about today is about IP addresses. How many IP addresses are there in China?

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IP address

Because I usually make a small program, build a website blog, etc., so when I buy a cloud server, I usually apply for a public IP.

Looking at the IP addresses I applied for, I suddenly thought of a question: Didn’t they say that IP addresses have been exhausted? Why can I apply for one easily? How many IP addresses does Alibaba Cloud have? How many IP addresses does China have in total?

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As you all know, our current Internet still mainly uses IPv4 addresses. Although IPv6 was being advocated when I was in college, so many years have passed and the status of IPv4 has not been shaken.

The IP address of IPv4 is represented by a 4-byte integer. Anyone who has studied programming knows that the range that 4 bytes can represent is 0-4294967295 (unsigned number).

That is to say, there are only 4.29 billion IPv4 addresses in the world. Of course, for the convenience of writing and memorizing, we usually do not use integers to represent, but use dotted decimal form.

From 0.0.0.0 to 255.255.255.255, divided into four bytes, each byte ranges from 0-255.

However, not all IP addresses can be used directly. Among these 4.29 billion, there are many IP addresses for special purposes.

When it comes to special IP addresses, I guess many people know the three ranges of private IP addresses:

• 10.0.0.0--10.255.255.255
• 172.16.0.0--172.31.255.255
• 192.168.0.0--192.168.255.255

In fact, in addition to these three ranges of IP addresses, there are many IP addresses for special purposes. Many articles on the Internet list a variety of them, but they are not complete. For a complete list of special IP addresses, you have to go to the IANA official website that manages IP addresses.

IANA

IANA, the full name of which is Internet Assigned Numbers Authority, is an organization that manages IP addresses, domain names and many other parameters used in the global Internet.

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On its official website, there is a document containing all the special-purpose IP addresses so far:

 https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml

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Many people know that 127.0.0.1 represents the local loopback address, but there is actually more than one loopback address. A total of 16777216 addresses from 127.0.0.0 to 127.255.255.255 are loopback addresses, and all data packets sent to these addresses will be looped back.

IP addresses are already precious. Isn't it a bit of a waste to use so many of them as loopback addresses?

Number of IPv4 addresses in China

The world's IP addresses are managed by five major regional organizations, and our country's IP addresses are allocated and managed by APNIC in the Asia-Pacific region.

There is also a public document on the APNIC official website that records all IP address information assigned by APNIC management. It is updated daily and can be obtained by visiting the following address:

 http://ftp.apnic.net/apnic/stats/apnic/delegated-apnic-latest

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The format of each line of this file is as follows:

 Registry|Country Code|Type|Starting Address|Number of IPs|Assignment Date|Status

The code for the mainland is CN, so the IPv4 address allocation in the mainland can be filtered out with a simple command:

 cat delegated-apnic-latest | grep "CN|ipv4" > cn_ipv4.txt

As you can see, as of December 1, 2021, a total of 8,614 network segments have been allocated in mainland China:

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Write a simple script to add up the number of IP addresses in all network segments:

 import sys
 total = 0
 print('target file: %s' % sys.argv[1])
 with open(sys.argv[1]) as fp:
 while True:
 line = fp.readline()
 if line:
 fields = line.split('|')
 ip = fields[3]
 num = int(fields[4])
 print('ip: %s, num: %d' % (ip, num))
 total += num
 else:
 break
 print('total: %d' % total)

The total number of IP addresses is: 343881984, accounting for about 8% of the entire IP address space.

Using the same method, we can collect data from Taiwan, Hong Kong, and Macau:

• Taiwan: 35688960
• Hong Kong: 12612096
• Macau: 336640

The total number is: 392,519,680, more than 390 million, accounting for about 9.14% of the entire IP address space. Is this data correct?

I consulted the "48th Statistical Report on the Development of Internet in China" released in September this year by CNNIC (China Internet Network Information Center), the domestic agency responsible for IP address allocation management.

Here is the data about IP address:

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This document gives data from June this year, showing that the number of IPv4 addresses in the country is approximately 393 million, which is basically consistent with the previous statistics. There may be slight discrepancies due to data time and other factors, but overall, it is certain that the number of IPv4 addresses in the country is around this scale.

Number of IPv4 addresses in Alibaba Cloud

Now that we have figured out the number of domestic IP addresses, the question is, how many IPv4 addresses does Alibaba Cloud have?

A piece of data was found in an IP address database under Taobao:

 https://ip.taobao.com/accurancy

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Of course, as we can see from the number of IP addresses in the mainland in the table, the data in this table is a bit outdated, but the order of magnitude should not be too different.

According to this data, Alibaba has about 3.7 million IP addresses. However, this is only the number of active IP addresses, not the total number of IP addresses stored by Alibaba.

So how many IPs does Alibaba have? In the public information, I only found data released in 2019:

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In the first half of 2019, the number of active IPs of Alibaba Cloud was 3.3 million, which was 400,000 less than the Taobao IP statistics above. This means that the number of active IPs increased by 400,000 in two years.

Two years ago, the total number of IP addresses in Alibaba Cloud exceeded 15 million. Two years later, this number will only increase. As far as several domestic cloud service providers are concerned, it can be said that Alibaba Cloud is far ahead.

It can also be seen from the above picture that Amazon is worthy of being the world's most powerful cloud computing company, with a total of 75 million+ IP addresses, and this is the data from 2 years ago.

At this point, the question at the beginning of the article has been clarified. Of course, the IP address obtained by purchasing a cloud server also has a lease period. For example, after the cloud server I purchased last year expired, the public IP address in it was recycled, and it may have been allocated to someone else.

Although IP addresses are in short supply, cloud server vendors have stockpiled a lot of them, and public IP addresses are constantly circulating in the pool, so we can get one for just a few hundred dollars.

Finally, here is a question for you to think about: What is the difference between the two IP addresses 0.0.0.0 and 127.0.0.1?

Author: Xuanyuan Wind

Editor: Tao Jialong

Source: Reprinted from the public account Programming Technology Universe (ID: xuanyuancoding)

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