Netalyzr - test internet connection

For many users, the Internet connection is characterized by only one parameter - connection speed. In reality, the quality of the connection is affected by a huge number of factors, as a result of which it is even very difficult for specialists to identify the causes of connection problems.

Researchers from the International Computer Science Institute (ICSI, Berkeley, USA) have developed Netalyzr , a test service for Internet users. The service is implemented as a Java applet, so Java must be enabled in order to run successfully in the browser.



At startup, Netalyzr conducts a large number of different tests using developer servers. In total, the applet contains 38 tests, some of which have subtests. Here are some examples of basic tests: port blocking, presence of hidden HTTP proxies and caches, manipulation of DNS queries, presence and behavior of NAT, MTU and fragmentation problems, IPv6 support, modem buffer size, etc. After testing is completed, the user is given a page with the results ( example ), on which individual tests are divided into categories and are marked with different colors depending on the outcome. A good review of tests for non-specialists was published by New Scientist.

ICSI researchers also store the results of all sessions on their servers for further analysis. About two months ago, at one of the conferences, an article was published detailing the service itself and the results of data analysis. At the time of publication, the applet was launched 130K times with 99K different IP addresses. The geography of the launch sites is as follows:



Data analysis revealed several prevailing problems: excessively large uplink buffers, leading to an unjustified increase in network latency; poor DNS resolver performance; difficulties with packet fragmentation; substitution of DNS query results by some providers and OpenDNS; etc.