recursive dns

: reverse query; 2: server status query; 3-15: unused.AA: occupies 1 digit, 1/8 bytes. Whether to send an authoritative response.TC: occupies 1 digit, 1/8 bytes. Because a UDP packet is 512 bytes, this bit indicates whether to cut over the part.RD: occupies 1 digit, 1/8 bytes. This bit is specified in the query and is the same in the response. Set to 1 to indicate that the server performs recursive queries.RA: occupies 1 digit, 1/8 bytes. The

DNS server ConfigurationI. DNS Overview: DNS is an abbreviation for the domain Name System and is a computer and network service naming system that organizes the domain hierarchy. Its role is: to convert the domain name into a network can recognize the IP address, the query results are saved and told to the client.Second, the

, feed the user, come out ah, I found, is x.x.x.x Think carefully, this and we Mail Express is the same ah, assuming you from the United States mail to Guangzhou Fanyu District, first express delivery to China (but there is no such as a root name server), and then down to Guangdong Province, followed by Guangzhou, and then down is Panyu.The above is the local domain name server iterative parsing process, in fact, can also be recursive query, here

ask F (sysu.edu.cn); Local domain name server: Hello, F, tell me the address of math.sysu.edu.cn; F: Swaiiow Look, alas, found, is x.x.x.x; Local domain Name server: Pale finally found, feed the user, come out ah, I found, is x.x.x.x Think carefully, this and we Mail Express is the same ah, assuming you from the United States mail to Guangzhou Fanyu District, first express delivery to China (but there is no such as a root name server), and then down to Guangdong Province, follo

resolve the address? There are two types of DNS queries: A recursive query (recursive) When querying a, you must know the answer once. A asks B, B doesn't know, but B knows C knows, so B gets the answer from C and tells 2. Iterative Query When a queries the answer, the method that is finally queried many times A asks B, B does not know, but B tells a

little common sense, assuming that a DNS server does not have a domain name test.com record information, when a client through it request to obtain test.com domain name information, this DNS server through the iterative recursive way from the test company actually store this record information DNS Server to obtain tes

Henan (China Telecom) Preferred DNS 222.88.88.88 Alternative DNS 222.85.85.85 Zhengzhou City, Henan Province (China Telecom) Preferred DNS: 219.150.150.150 Backup DNS: 219.150. 32.132 Zhengzhou City, Henan Province (China Netcom) Preferred DNS: 202.102.224.68

First, what is DNSDNS (domain Name System), a distributed database of domain names and IP addresses that are mapped to each other on the Internet, makes it easier for users to access the Internet without remembering the number of IP strings that can be read directly by the machine. The process of obtaining the IP address of the host name through the hostname is called Domain name resolution (or hostname resolution). Two ways of DNS query1)

server to allow the Peer to add an MX record for you. The record format is as follows:Your domain name in mx 10 mail.mydomain.comWhat is the TTL value?The full name of TTL value is "Time To Live". Simply put, it indicates the cache Time of DNS records on the DNS server. To understand the TTL value, take a look at the following example:Assume that the IP address of the domain name myhost.abc.com (in fact, t

"/>Configuration file curly braces should have spaces on both sides192.168.3.132-----The named.conf file configuration for the primary DNS serverOption under:listen-on specifies which port on which address to listen ondirectory specifies the DNS server working directory, which is where zone files are placedAllow-query specifies that the host of those network segments can be resolved through this

true satisfactory explanation was given to this ancient and important series: any adjacent two numbers in this series, which are divided by the same number, are the most closely proportional to 0.618034 ... This value, its limit is the so-called "Golden partition number". 2. To find the nth Fibonacci numberThe nth Fibonacci number is simpler to apply directly to the formula N = 1, 2 o'clock, fib (n) = 1;n > 2 o'clock, fib (n) = fib (n-2) + fib (n-1) at the time of calculation there are two algo

address that allows DNS query. The default value is localhost; Recursion: Set recursive queries. Yes: cloud-based recursive queries. No: recursive queries are not allowed. Recursive queries are allowed by default. Section 2: 1 Logging {# define log 2 3 channel default_deb

I. What is DNS?DNS (domain Name System), the Internet as the domain name andIP Addressone of the mutual mappingsDistributed DatabaseTo make it easier for users to accessInternet, instead of remembering the number of IP strings that can be read directly by the machine. ThroughHostname, the process of eventually getting the IP address for that hostname is called Domain name resolution (or hostname resolution)

: unused.AA: occupies 1 digit, 1/8 bytes. Whether to send an authoritative response.TC: occupies 1 digit, 1/8 bytes. Because a UDP packet is 512 bytes, this bit indicates whether to cut over the part.RD: occupies 1 digit, 1/8 bytes. This bit is specified in the query and is the same in the response. Set to 1 to indicate that the server performs recursive queries.RA: occupies 1 digit, 1/8 bytes. The DNS serv

For the use of PHP recursive functions, share several PHP Recursive FunctionsExample, in PHP programming, using recursive function calls is very common, recursive function is good, can improve code efficiency, through example learning the use of PHP recursive functions。 Fir

This article will introduce several main DNS attack methods. I hope this technology will help you. Use DNS servers for DDOS attacks The normal recursive query process on the DNS server may be exploited as a DDOS attack. Assume that the attacker knows the IP address of the attacked machine, and then uses the IP address

description) The. Root DNS server is represented by a symbolic dot. . Com. net. org. cn. tw primary domain name Linux IdC.com second-level domain name Therefore, our usual website such as www.linuxidc.com is actually www.linuxidc.com. The last point points to the root server. (1) What types of queries does a DNS server actually store database files corresponding to the domain name and IP address? The

How does a php recursive function work? Typical examples of php recursive functions: Usage of php recursive functions Php Recursive functionsFor example, in php programming, it is very common to use recursion for function calls. recursive functions are used well to improve c

address error to wait for the cache to clear and then re-resolve to obtain the address. General cache cleanup is about 2 hours.3, the DNS service access relationship, the client Access DNS server is recursive, the DNS server must give the client a result. While the DNS serv

How do I set up the notebook DNS? Recently, 2 laptops in the home when browsing the Web page, often inexplicably random pop-up some ads, and these ads are not on the Web page, guessed a bit, should be the network of broadband operators were hijacked caused. To solve the problem of network hijacking, there are 2 methods, one is telephone contact network business, the other is to modify the computer DNS, shie