[PConline by-talk] whether had you also encountered such situation, want to visit a website when us namely when, the page shows is really " cannot visit this website " , how is this to return a responsibility? If the examination discovers Ping was illogical, this may be concerned with DNS. So, is what DNS? Is the DNS that often hears hijacked what is those who point to?
Alleged DNS, it is the abbreviate of Domain Name System actually, the interpreter comes over is domain name system. As domain name and IP address a distributed database of mutual map, its mainest effect translates the domain name into IP address namely, make thereby we more visit Internet conveniently.
IP address should need not say more? It is a kind of when IP agreement offers unified address format, each network that goes up for Internet and each lead plane allocate a logistic address, come with this the difference of screen physics address. The commonnest, need to have IP address on the PC that is every couplet net, ability corresponds normally. IP address is a 32 binary system is counted, be broken up to be 4 normally " 8 binary systems are counted " (namely 4 byte) , with " enter bit minutes make " express as (A.b.c.d) form. For example 192.168.100.1.
The domain name can say the generation that is an IP address says, the purpose is to go to the lavatory we remember IP address. For example, wikipedia.org is a domain name, as corresponding as its IP address is 208.80.152.2. We can visit Wikipedia.org to replace IP address directly, next domain name system (DNS) the IP address that can change it into facilitating machine to identify. And had DNS, we do not need to remember the many IP address of each website, and need to know the domain name of this website is OK only.
Change character, input a domain name when we visit a website, it is DNS is helping you analytic visit specific IP address. But do you know? Once so important DNS perhaps is hijacked by pollution, will bring about a website to cannot be visited normally. Business of certain network operation, for certain purpose, may restrict certain user to visit certain and specific website, and limitative method is the most commonly used is DNS pollution is hijacked with DNS.
First for say DNS is polluted, say cache of domain name server sends poison again, show those are made painstakingly or make the package of data of domain name server that come out inadvertently, point to the domain name incorrect IP address. Normally, DNS inquiry does not have any attestation mechanisms, and the UDP that DNS inquiry is based on normally, be without the agreement with fluky join, bring about DNS inquiry to be distorted very easily, through be opposite the 53 DNS that go up inquire UDP port undertake inbreaking detecting, once discover the request that matchs with keyword photograph, the analytic server that pretends target domain name instantly (NS) the person that give inquiry returns false result.
Once the cache of the server of bureau region domain name of relevant net region is polluted, can guide the computer inside net region the network address that is made toward wrong server or server. Accordingly, simple point says, what DNS pollution points to is pretend oneself into DNS server, after the examination visits certain website to the user, make a domain name analytic the IP address to the mistake.
Say DNS pollution, what is DNS is hijacked? Actually, DNS is hijacked is the request that shows domain name of the intercept inside the network limits that hijacking is analytic, parse the domain name of the request and examine the request discharged beyond limits, the IP address that returns a holiday otherwise or whats are done make request to lose answer, its effect cannot be visited to specific network namely or of the visit is false network address. Change character, DNS is hijacked even if adopt illegal measure, get the limits of authority of DNS server, undertake DNS configuration modification next, make a domain name analytic the IP address to the mistake.
Such looking, both look to have some of likeness it seems that, is its distinction in where? Above all, DNS is hijacked is to hijack DNS server, revise its then analytic result; DNS pollution is domestic certain server undertakes inbreaking detecting to DNS inquiry, discovery requests with what match on blacklist, this server becomes DNS server with respect to camouflage, the person that give inquiry returns false result. It used UDP agreement is not to have join unreliability. That is to say, one is to hijack DNS server, one is to pretend DNS server, the result that create is the IP address that returns an error.
See here, everybody was clear about ~
