An Analysis Of Dns Cache On Windows Operating System

Domain Name System is a kind of very basic service used for mapping domain names to IP addresses. What we do the most frequently online is to sending DNS request to get site addresses. HTTP is a kind of application level protocol faced to object put forward in 1990 and has been developed consistently. It is a Hypertext Transfer Protocol used extensively for www global service which is popular on line nowadays.Personal computer can cache the address information returned by DNS server which can to some extent reduce the visit to DNS server in Windows Operating System. Personal computer determines the lifetime the information exists in the cache according to the TTL value returned by DNS server. So the TTL value has direct relation with the caching effect.According to the studying of long term, I found the personal computer visit DNS server too frequently, so I doubt the bad caching effect is due to that the TTL value was not set properly. According to the Analysis of comparing DNS data with HTTP data, I found that the personal computer also visit DNS server too frequently indeed on huge data.At the same time, the popular Webs which their numbers have a lower percent, have the small ttl and a large num of visits. By contraries, although the Webs which are not popular have the big ttl and fewer visits, their numbers have a higher percent. Because of the small ttl setted by the popular Webs in general, this paper concludes that the TTL value is generally low which results in that the PC cache does not play role in network visit, and the personal computers will visit DNS server so frequently that the DNS server has to bear so many unnecessary visits.