Domain Report 2020
CZ.NIC, z.s.p.o, is an interest association of legal entities, founded in 1998 by leading providers of Internet services in the Czech Republic. The principal duties and activities of the association include operation of the .CZ domain registry and DNS servers for the .CZ top-level domain (TLD).
The annual domain report is an on-line publication that offers key statistical facts about the status and dynamics of the Czech country-code TLD (ccTLD), which is primarily used by subjects in the Czech Republic – individuals and organisations.
The graphs and tables are organised into several sections illustrating various aspects of the registry and domain operation. Most charts are interactive: additional information can be obtained by placing the mouse cursor over graphical components of such a chart. In multivariate graphs, each variable can be switched off or on by clicking on the corresponding entry in the legend.
Domain registrations
In the previous domain report we observed clear signs of saturation in the number of second-level domains registered under .CZ, and predicted a stagnation or even decline in 2020. However, the following chart shows that this prediction turned out to be false: the number of domains rose to 1.37 million, which means a 3.2% increase compared to the end of 2019.
The rather significant growth in 2020 was undoubtedly caused by the COVID-19 pandemic. This can be seen in the following chart that shows monthly domain registrations in the last three years. The largest relative increases in 2020 can be observed in the periods March–June and October–December that coincide with the pandemic waves.
At least 2,500 domains registered in 2020 are likely to be directly connected to the pandemic in that their labels contain at least one of twelve selected COVID-related word stems, such as corona/korona, covid, virus or respirator. Daily numbers of such registrations, as well as their cumulative sum, are displayed in the next chart. See ADAM report 1/2020 for additional details.
Domain geography
Each domain is registered for a concrete domain holder, which may be a person or a company – each holder type has a share of almost exactly 50%. Most of the .CZ domains (1.27 million, i.e. 92.8%) naturally have holders with Czech addresses. The following table and map show their distribution among the 14 regions of the Czech Republic, as well as the number of domains per 100 citizens.
| Region | Domains | Domains per 100 citizens |
|---|---|---|
| Praha | 409 145 | 31.03 |
| Jihomoravský | 154 490 | 12.98 |
| Středočeský | 132 276 | 9.57 |
| Moravskoslezský | 96 842 | 8.06 |
| Zlínský | 58 226 | 9.99 |
| Jihočeský | 52 858 | 8.21 |
| Ústecký | 50 667 | 6.17 |
| Pardubický | 48 096 | 9.22 |
| Královéhradecký | 47 883 | 8.68 |
| Olomoucký | 44 539 | 7.05 |
| Plzeňský | 42 713 | 7.25 |
| Vysočina | 37 291 | 7.31 |
| Liberecký | 36 786 | 8.30 |
| Karlovarský | 15 404 | 5.23 |
| Unknown | 45 496 | NA |
The share of foreign domain holders is currently 7.2%. Top ten countries are shown in the table below.
| Country | Domains | ||
|---|---|---|---|
Slovakia
|
Slovakia | 24 397 | 24397 |
Germany
|
Germany | 14 923 | 14923 |
United States
|
United States | 10 079 | 10079 |
United Kingdom
|
United Kingdom | 5 419 | 5419 |
Poland
|
Poland | 5 123 | 5123 |
France
|
France | 4 358 | 4358 |
Netherlands
|
Netherlands | 3 951 | 3951 |
Switzerland
|
Switzerland | 3 133 | 3133 |
Bahamas
|
Bahamas | 2 999 | 2999 |
China
|
China | 2 526 | 2526 |
| Other | 21 463 | 21463 |
The changes in last three years are shown in the following slope graph. An interesting case is Bahamas – the number of domains held there grew from 70 to 2,999.
Domain names
Each second-level domain is identified in the .CZ registry by a
unique label (the part before .cz). According to
RFC 1035, it
may consist of at most 63 characters. Excessively long domain names are
of course not very convenient, so only five of the .CZ domains have
their labels with the maximum length. On the other hand, short labels
are much more popular. In particular, all 36 one-character labels (26
letters and 10 digits) are already taken.
The following histogram shows the actual distribution of label length. The median is 10 characters.
Domain as seen by resolvers
CZ.NIC currently operates more than 120 DNS servers for the .CZ zone, distributed in 12 countries of 4 continents. On the average, they are contacted by about 1.25 million distinct resolvers every day that send around 16 thousand DNS queries per second (QPS). The resolvers’ requests are delivered to the “closest” server based on IP anycast routing configuration. The resulting global communication pattern is depicted in the following diagram showing average QPS distribution from top-15 countries in the last three months of 2020.
Topological distance between a DNS resolver and the responding authoritative server affect the latency of DNS transactions, which is an important factor contributing to the overall experience of Internet users. Since 2019, CZ.NIC has been conducting a regular analysis on reachability of .CZ servers with the aim of obtaining relevant data that can be used for planning future server deployments.
In the next graph, the mean round-trip time (RTT) is plotted against the mean QPS for 22 geographical regions. The arrows indicate how each region moved in this graph since October 2019.
We can see a decrease in mean RTT for all regions except Micronesia. The regions that are important sources of DNS queries (near the right edge of the graph) already benefit from a very good RTT. The reachability of .CZ servers has also improved considerably for the regions of Eastern and South-Eastern Asia during the last year, mainly due to the deployment of two new servers in Singapore.
IPv6
The following graph illustrates the evolution of IPv6 support among .CZ domains in the last ten years. The classification is based on the version(s) of DNS servers’ IP addresses for each second-level domain. 32.5% domains support both IPv4 and IPv6, and 101 domains have DNS servers with no IPv4 address.
DNSSEC
DNS Security Extensions (DNSSEC) use public key cryptography for securing DNS data. In the past decade, CZ.NIC has been investing a lot of effort into dissemination and actual deployment of DNSSEC in second-level domains. The .CZ domain was also among first top-level domains to implement DNSSEC.
DNSSEC deployment
The following graph shows the growing number of DNSSEC-secured second-level domains (blue bars) in comparison to the total number of .CZ domains (black line).
In 2020, the fraction of DNSSEC-protected domains crossed the threshold of 60%. According to the ranking published by Viktor Dukhovni, the .NO is the only ccTLD with a higher penetration of DNSSEC than .CZ (63%).
DNSSEC algorithms
An important operational aspect of a robust DNSSEC deployment is the selection of a cryptographic algorithm. The following chart shows how the mix of cryptographic algorithms in the .CZ domain evolved since 2008.
As we can see, RSASHA1 had been an absolutely dominating algorithm until 2015 (RSASHA1-NSEC3-SHA1 is the same, only serves certain backward compatibility purposes). This algorithm uses the SHA-1 cryptographic hash function that is known to be weak but, according to the current recommendations still poses no significant threats to DNSSEC integrity. The previous chart shows that almost 70% secured second-level domains in .CZ now use a stronger algorithm.
DANE
DANE (DNS-based Authentication of Named Entities) is a technology that uses the DNS hierarchy together with DNSSEC to validate authenticity of X.509 digital certificates.
Out of 589 070 unique mail servers specified in MX
records for all .CZ second-level domains, 667
(0.11%) had a corresponding DANE TLSA
record. Due to the concentration of mail services, the fraction of .CZ
domains using DANE-protected servers is significantly higher –
10.8% (148 124 domains).
We also identified 170 domains with DANE records for
web services running on either www.<domain>.cz or
<domain>.cz. This small number (which is even less
than last year) is a consequence of the fact that, for several reasons,
DANE has so far been largely ignored by browser vendors, and their
attitude is not likely to change in the future.
Server software
This section contains estimates of the market shares achieved by implementations of the most common Internet services: DNS, web and e-mail. Data was obtained by querying all second-level domains using the DNS crawler tool in December 2020. These results have to be taken with a grain of salt, as they depend on the willingness of server administrators to disclose the correct information. Note also that one domain name may be assigned to several different servers. If these servers use different implementations, then the same domain is counted for all implementations.
Web servers
Web services in the .CZ domain are mostly run on Apache and NGINX servers. The following histogram
shows market shares of most common web server implementations detected
for the “main” page of each second-level domain, i.e. either
www.<domain>.cz or just
<domain>.cz.
Mail servers
Finally, the following table shows the market shares of mail server
implementations. Included are all servers specified in MX
records of second-level domains.
| Software | Domains | Hosts |
|---|---|---|
| Unknown | 776 641 | 459 270 |
| Postfix | 520 263 | 152 980 |
| Exim | 36 962 | 6 542 |
| Microsoft | 31 245 | 29 148 |
| IceWarp | 21 220 | 17 437 |
| Haraka | 11 360 | 123 |
| Sendmail | 5 815 | 990 |
| Kerio | 1 185 | 731 |
| Symantec | 401 | 125 |
| qmail | 318 | 22 |
| Barracuda | 177 | 54 |
Web contents
DNS crawler is also used for downloading web page contents of all second-level domains, see the project description for details. This large data set was then used for classifying domains according to the character of their main web pages. In order to get more insight into the effects of the pandemic, we separately processed the following two cases:
- all second-level domains in the .CZ registry
- domains that were (last) registered in 2020.
First, we applied an automatic machine-learning classification as described in ADAM report 2/2020. Here are the results:
The most striking difference between the two cases is the massive increase in the relative frequency of parked domains in the 2020-only case – speculative domain registrations were apparently mushrooming during the pandemic.
For both cases, the web pages in the Normal category were further classified manually into 14 content-related subcategories, using two random samples of 1,200 domains each:
It is not surprising to see a relative increase in 2020 registrations of e-shop domains, given that normal retail business was halted throughout most of the last year.