So, here DNS is one of the fundamental things on which the work of the entire Internet is built. This abbreviation stands for Domain Name System, which means domain name system.
I already touched on this issue (the device of the domain name system) when I talked about that, but only in passing. Today I want to talk about the role of DNS servers in the operation of sites and the entire Internet as a whole.
Why are DNS servers needed and what is it?
The domain name system operates with fully-fledged names (Latin letters, numbers, dashes and underscores are allowed when they are formed) ..120.169.66 is not informative) and they are easier to operate.
The latter refers specifically to the human factor, because it is still more convenient for machines to use IP addresses, which they do. can get from the DNS server.
It is on these DNS servers (sometimes they are also called NS from the Name Server, i.e. name server) and the entire Internet is supported (like a flat world on three whales standing on a turtle). which does not require the direct participation of a person in its work (set it up - it plows in 24/7 mode). And there are a lot of such DNS servers on the network.
How does DNS work and what does the Hosts file have to do with it?
At the dawn of the Internet DNS didn't exist at all. But how did the network work then?.120.169.66? For this business then (and now too) the so-called was responsible, where all the hosts of the then small Internet were registered.
Such a file was (and is now) on each user's computer (it is also on yours) connected to the network (see the link above for how to find it).
In the hosts file several thousand lines were written (according to the number of sites on the Internet at that time), in each of which the IP address was first registered, and then the corresponding domain, separated by a space. This is what an entry for my blog would look like if it existed on the web twenty-five to thirty years ago:
109.120.169.66 site
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The DNS database is maintained using a hierarchy of DNS servers that communicate using a specific protocol.
Initially, the role of DNS was performed by the text file hosts, which was formed on the central node and then sent to each computer on its local network.
What is a DNS server used for?
Without going into details, let's say that the DNS server is a mechanism that converts human-readable alphanumeric names of network devices (domains) into their .
Interesting! A group of several IP addresses can belong to one domain name. a large mail server is often not one server, but several. The purpose of this approach is to create redundancy - if there is a problem with one server, another takes over its functions. All these technological features are hidden from the eyes of an ordinary user, and the task of providing the necessary resource according to the request lies with the DNS server.
The most important indicator when choosing a DNS server is its availability in time.
For example, if the server you have chosen does not work, then you can access the Internet only using the IP addresses of sites or by specifying a different DNS server.
Based on practice, let's say that in order to solve most problems, you will need to remember only 2 IP addresses: 8.8.8.8 and 8.8.4.4.
The advantage of these servers is, firstly, a high degree of availability, and secondly, they are very easy to remember.
What DNS server are you using?
To find out which DNS server is being used, you need to:
- In the "Open" field, you must enter or copy from the site the command to call the command line - " control /name Microsoft.NetworkAndSharingCenter(without quotes) and click OK.
Type on the keyboard Win + R.
In the window that appears, select the required profile (if there are several) and go to the "Local Area Connection" menu.
- In the "Local Area Connection Status" window, click the "Details" item and go to the window with information about our connection, and then find the line "IPv4 DNS servers".
DNS troubleshooting algorithm
Sometimes, a situation may occur when the DNS server is unavailable. This situation can arise for two reasons:
The problem on the client side is usually the stopping of the DNS client service on the computer. The DNS Client service needs to be started.
The problem is on the side of the provider or organization of the DNS server that you use. You need to change the DNS server.
To start the DNS client service, you must:
Click "Start", in the search field we write "services" (without quotes) and go to this menu.
In the window that opens, we will see all the services that are involved in the system. We are looking for the "DNS client" service. We need to make sure the DNS service is running. In the field "Status" should be the inscription "Working".
If the field is empty, then the DNS service is stopped and needs to be started. To start the DNS service, you need to right-click on the service and click "Start" in the context menu.
After starting, pay attention to the "Status" field, the inscription "Working" should appear.
If the DNS client service is running and you can only access the site by its IP address, try changing the DNS server.
As a rule, the time that the system spends on connecting to the DNS server when visiting web resources is small. Most often, those servers that the provider uses by default work stably and quickly. However, there are situations where standard DNS is not fast enough. In this case, you can try changing the server.
Google Public DNS
According to the developers themselves, this DNS can significantly speed up the loading of web pages. In order to use this server, in the connection settings, you must specify the addresses 8.8.8.8 and 8.8.4.4 for the primary and secondary DNS, respectively.
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Following the example of Google, Yandex has developed its own alternative DNS server. In addition, the developers have added family control options in case it becomes necessary to block potentially dangerous resources. To use DNS without filtering functions, you must enter the address 77.88.8.8 in the connection settings. If you enter the address 77.88.8.88, you can use the dangerous resource filtering features. In the event that you enter the address 77.88.8.7, you will activate the filtering of dangerous sites and porn resources.
This service is quite popular on the net and for good reason. OpenDNS allows you to use modern methods of protection on the Internet, is fast and has many nice features, for example, the function of correcting typos in dialed addresses.
The service has paid and free modes.
Free mode with standard settings is available at the following addresses:
- 208.67.222.222
- 208.67.220.220
SkyDNS
This service is a leader in the Russian-speaking Internet in the field of security and inappropriate content filtering. As the developer himself assures, the service is used by tens of thousands of users, large companies, Internet providers, etc. Paid and free modes are available.
Connection to the free mode is available after completing the registration procedure, which will not take much time. To use SkyDNS, you will be prompted to download a small SkyDNS Agent application, or provide your IP. However, you can use the service without installing the application.
To do this, you will need to specify the DNS address 193.58.251.251.
In addition, to search for a suitable DNS, you can use the appropriate software, which is quite a lot on the Internet.
From the local network of the home router - you can provide access not only to the Internet, but also to the resources of the router itself.
We can talk about an FTP server where a USB drive is used as a disk, etc. At the same time, it is possible to make all these resources available from an “external” network. For what, the “dynamic DNS” service is usually used. We will look at how to set up DDNS on a router.
Local and "external" network
First, let's try to explain how DDNS is used. From the local network, the router itself is available at the same address (for example, 192.168.10.1). In the "outside" network, the WAN port is assigned a specific IP address, which in most cases is changeable. Remembering it is useless, since the value can change at any moment. But it is possible to access the router without using the IP "explicitly". It is enough to register once in the corresponding service and configure the DDNS option in the router.
After setting up DDNS, access to the router is carried out by a domain name (which, in addition, the user himself can come up with). This is convenient, but on condition that everything is configured correctly.
How to register in DDNS service?
Paid and free services
Here is a list of addresses of sites providing DDNS service:
- no-ip.com
- 3322.org
- dyndns.org
- dhs.org
- update.ods.org
- dyns.cx
The most famous of them is Dyndns. All tuning examples, as a rule, are given “under it”. But this service has recently become paid. So, you need to look for a free service (of those that are supported in the router).
It is important to know that a router of a certain model may only support some of the DDNS services.
Consider an example for TP-Link devices:
Dynamic DNS tab
As you can see, in routers of this brand, you can use 1 of 3 different services (but no more). Their list is available on the DDNS settings tab. What is true for routers of different models.
Registration in the service
Before setting up the router, you need to register in the DDNS service. You need to get a domain name (the service will check it for uniqueness), and only then this name will need to be specified in the settings.
An email is required to register. New user card - usually contains information: first name, last name, region, e-mail. If you need to specify a zip code, you can leave this field blank.
As a result, the user will have at his disposal a unique domain name. For example, this: "1234router.no-ip.biz". Also, an account is created to manage the account card (you need to remember the login and password for it).
How to set up DDNS in a router?
DDNS Settings Tab
It is the DDNS option in most routers that is the easiest to configure. The web interface should have a tab containing all the required parameters: domain name, login with password, list of services.
Setting algorithm:
- Go to the required tab (usually, "DDNS" or "Dynamic DNS" in the "Advanced Settings" section)
- Choose a service (the one you signed up with)
- Fill in all empty fields
- If there is a checkbox "Enable" - set it, and be sure to save the settings:
Setting up DDNS in TP-Link routers
Connect the router to the DDNS service - the user must open the interface and click the "Login" button (on the tab discussed above). The connection will remain active until the router is rebooted.
DDNS Usage Example and Known Issues
Let's say everything was done correctly, and additionally, an ftp server is enabled on the router. Then, from anywhere in the world - this server becomes available at the following address: ftp://1234router.no-ip.biz:80. The example is of course correct if the domain name "1234router.no-ip.biz" was obtained.
Sometimes it happens that by domain name - the router, nevertheless, becomes unavailable. In this case, just go to the service website, open an account (or specify a domain name) - and the IP of the router will appear in the window on the page. The problem is that after a while this IP may change.
But, in principle, this method is also relevant: instead of “1234router ...”, an IP address is indicated (which is actually assigned to the WAN port). The ability to see the IP value is provided by any of the services, and without any problems.
Additionally, we note the main difference between DDNS and 2IP.ru and the like: you can find out the IP of the router using DDNS from any device connected to the Internet (from anywhere in the world). Further, this IP is used to access the router.
An example of setting up a D-Link router under DynDSN
But for now, we'll just talk about why you might want to change your DNS server.
Speed increase possible
Third party DNS servers may be faster than your ISP's DNS servers. This is not guaranteed, it will depend on your geographic location, how close third-party DNS servers are to you, and how slow your ISP's DNS servers are.
If all you want is good speed, you may or may not see the benefits of switching to a third-party DNS server. To find out for sure, you should run a DNS benchmarking tool like Namebench, which will make DNS queries to your current DNS server and other DNS servers, checking how long each of those servers takes to respond.
Popular third party DNS providers such as Google Public DNS or OpenDNS may be faster for you. If so, Namebench will let you know.
Note that Namebench cannot evaluate the effectiveness of each factor. For example, Google Public DNS and OpenDNS participate in , which allows the participating DNS services to know your IP address and respond from IP addresses that are closer to you, thereby increasing the speed of communication. Other DNS servers, like those offered by your ISP, are not as agile in implementing these new technologies.
Possible improvement in reliability
This is closely related to the already noted possibility of speed improvement. If your ISP doesn't care too much about keeping their DNS servers fast and stable, you may experience periods when websites fail to load or when they load very slowly due to too long DNS queries. If your ISP is not doing its job properly, switching to a third party DNS server can bring you more reliability.
Parental control
If you have young children and want to set up web filtering, there are many different ways to do it. One of the easiest ways to set up web filtering is to change your DNS servers to OpenDNS servers. Change the DNS server on your router and you can configure parental controls on the OpenDNS website, allowing you to block certain categories of websites and view websites accessible from your home network.
This is especially convenient because after changing the settings on your router and setting up parental controls on the OpenDNS website, the settings will be applied to every device on your home network - PCs running any operating system, game consoles, smartphones, tablets, etc. When a DNS query for the IP address of such a website has been sent, OpenDNS returns a different IP address. The user's browser connects to this address and receives a message that the website they are trying to access has been blocked.
Please note that this is not very reliable. A user on your network can simply change their device's DNS server to bypass the filtering. Young children won't be able to do this, but teens might as well - just as it is with most other parental controls.
Phishing Protection
OpenDNS also performs filtering to block phishing sites. Modern browsers have built-in anti-phishing protection, but if you're on a network that includes PCs running Windows XP and Internet Explorer 6, then using OpenDNS will give all those PCs some identity theft protection they wouldn't otherwise have. .
Other DNS services do not offer this feature. For example, Google Public DNS does not include content filtering features, as it aims to simply function as a fast DNS service without any frills.
Means of protection
Third-party DNS servers, such as OpenDNS and Google Public DNS, also offer security features that have not yet been implemented in the DNS servers of many providers. For example, Google Public DNS supports DNSSEC to ensure that DNS queries are properly signed and trusted. Your ISP's DNS servers may not have implemented these security features yet.
If the SOPA bill were passed, then no US DNS servers would support DNSSEC because SOPA would outlaw DNSSEC. If Americans wanted to have the benefits of DNSSEC, they would be forced to use overseas DNS servers.
Access to content blocked by geographic criteria
Special third-party DNS servers may also allow you to access certain geo-restricted content. For example, by switching to Unblock-Us you can access media such as Netflix, Hulu and BBC iPlayer no matter where in the world you are. When your computer makes a DNS request, the DNS service does some tunneling to make the service assume that you are somewhere else in the world. This is a handy feature because it allows you to access these services from any device by simply changing the DNS server on your router.
You shouldn't use a free service as your primary DNS service - switching to it will definitely slow down your web browsing. If you use one of these, you need to use a tool like DNS Jumper to quickly switch to it when you need it and switch back when you're done.
Both work in the same way and do not have this limitation, but on the other hand, you will have to pay for them.
Web Censorship Bypass
Some ISPs and states only block websites at the DNS level. For example, an ISP might "block" example.com by redirecting its input DNS to another website. If a website is blocked by this method, replacing your DNS server with a third party DNS service that does not block that website will allow you to access it. An example is the case that occurred at the time when The Pirate Bay was blocked in the UK. People could change their DNS servers to use it again.
Note that websites are often blocked at the IP level, so this won't always work. For example, the firewall uses many techniques to block websites, including DNS blocking.
Namebench includes an option that checks DNS servers for censorship to determine if the results of current DNS servers are being censored.
If you want to change DNS servers, then you will probably want to change the DNS server on your router, which will affect your entire home network. You can also change the DNS server on a single computer, which will only affect that particular computer.
What DNS services do you use? For what purpose? Share your experience and settings in the comments.
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