What is a two-level domain name?

I heard that the application domain name to two domain names, one is with the WWW, one is not with, and heard that no www is a two-level domain name, do not know is this, there is no three-level domain name, four-level domain name, simply N-class domain name.

Reply to discussion (solution)

If you use a variety of cloud services, you will provide a level two domain name
Example: abc.sinaapp.com

Let's just say, for example, my domain name is www.abcdefg.com.
Then my two-level domain name can be defined, or the service provider to determine it?

Let's just say, for example, my domain name is www.abcdefg.com.
Then my two-level domain name can be defined, or the service provider to determine it?

Domain management background can be set up classification.

The domain name consists of the root domain, the domain name, and the host name three parts
A level two domain name refers to the domain name that you are requesting from your domain service provider that does not contain a host name
That is, the abcdefg.com part of www.abcdefg.com, plus the hostname's domain name by yourself.

The domain name consists of the root domain, the domain name, and the host name three parts
A level two domain name refers to the domain name that you are requesting from your domain service provider that does not contain a host name
That is, the abcdefg.com part of www.abcdefg.com, plus the hostname's domain name by yourself.

So if I want to parse a two-level domain name again, like Cade.abcdefg.com, does that mean that Cade is a server name?

Yes
As long as your domain name is supported by the two level domain name (you can confirm this to the service provider)

Yes
As long as your domain name is supported by the two level domain name (you can confirm this to the service provider)

So do I say that I have to pay extra money to the domain name provider, for this level two domain name

I don't know, you should ask the service provider.

Yes
As long as your domain name is supported by the two level domain name (you can confirm this to the service provider)

So do I say that I have to pay extra money to the domain name provider, for this level two domain name

So far, I have not seen the need to pay extra money. Register a domain name, his subdomain is for you to use.

As long as you have a domain name, two-level domain name resolution can be used,

For example, the first level domain name http://www.abc.com, the level two domain name is in the first level domain name own definition sub-domain name, for example: http://123.abc.com or/HTTP Xyz.abc.com, are two-level domain name, two-level domain name based on a first-level domain name for resolution, three-level domain name based on two-level domain name resolution, such as set a successful http://xyz.abc.com, and then set the HTTP//at the bottom Abcdefg.xyz.abc.com, become level three domain name, n level domain name layer set, same reason can get.

Level two domain name is not directly in the configuration file of the server program to set it all right?

For example, the first level domain name http://www.abc.com, the level two domain name is in the first level domain name own definition sub-domain name, for example: http://123.abc.com or/HTTP Xyz.abc.com, are two-level domain name, two-level domain name based on a first-level domain name for resolution, three-level domain name based on two-level domain name resolution, such as set a successful http://xyz.abc.com, and then set the HTTP//at the bottom Abcdefg.xyz.abc.com, become level three domain name, n level domain name layer set, same reason can get.

If it is your own definition, then it seems that the use of two or two or more domain names will not pay to use it?

To put it simply, you have to face three businesses: Registrars, domain name resolvers, space (server) vendors
Registrar just register domain name such as xxx.com, the registration allows you to specify a DNS (domain name resolver), can change, this fee difference is generally not small
Domain name resolver to help you resolve xxx.com to an IP (server), can also parse the prefix xxx.xxx.com to the corresponding IP, whether to pay to see the service, generally will provide free www this prefix, is www.xxx.com
The space supplier is the owner of the IP mentioned above, can give you space to store and open for the Web (HTTP) service, the cost depends on the service agreement

You're in a situation where two or three of the three businesses above are in the same home, and there's a merger charge.

So when you register the most important is to find a trusted domain name registrar, you have the right to change DNS, or your domain name resolution right in the hands of others, when there is a dispute, he will be able to make your site can not find (no matter what space you change, you can not specify DNS is useless), this kind of thing I see much. Of course, if the legal document records that you are the domain owner, you can appeal to the Domain name Management Center to retrieve control, but these are clerical requests, formalities are quite troublesome.

If you want to prefix the domain name without paying, there are two ways:
1. You are the role of the domain name resolver, of course, you have to have the relevant DNS server or similar software, if the sub-domain name is not many, not necessarily the server hardware, but the bandwidth and concurrency of the response capacity is to be satisfied
2. Now there are some free domain name resolver, you can find yourself, because it involves the wall of the problem, there is not much to say

General business is not too dark, find a credible, can set up their own DNS, you can add a certain number of name records is sufficient

The above brothers said more clearly:

Www.baidu.com level, but in the case you directly in the browser input baidu.com, that is to say www can be omitted.
Wenku.baidu.com is two levels, can not be omitted, the front cannot add www.
Level Three is similar, the leftmost domain name, followed by a point ".", followed by a level two.
Level four can be referred to level three.

A little confusing.

There's no answer to the charging question yet.

There's no answer to the charging question yet.

You didn't see that, did you? I'm pretty clear about that.

There's no answer to the charging question yet.

You didn't see that, did you? I'm pretty clear about that.

I'm talking about a two-level domain name or a three-tier domain fee.

There's no answer to the charging question yet.

You didn't see that, did you? I'm pretty clear about that.

I'm talking about a two-level domain name or a three-tier domain fee.

I said to see the service, there is no international this charge, just see if the DNS service providers, that is, the different home, from free to sky-wide possible
Theoretically ~ should be free, but this also account for server resources, so service providers may also limit, large businesses have the ability to add unlimited
If your registrar does not provide multi-level domain names, but can let you modify the specified DNS, you can specify to an additional free or paid DNS service provider there

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