INL: IP Networking Lab - dns

DNS prefetching : browser optimisations may cause DNS server overload

obo — Thu, 10 Mar 2011 22:36:45 +0000

Recent browser have added an optimisation that enables the browser to resolve all the DNS names that appear inside a visited HTML page while the browser displays the HTML page. This can speed up the retrieval of the next link on which the user will click. Unfortunately, on websites that contain a large number of different hostnames on each page (e.g. pointers to homepages of users who have posted comments), this may lead to a large number of DNS requests for each HTML page retrieved.

H root server down for 18 hours

obo — Sun, 03 Oct 2010 21:14:03 +0000

The root servers of the Domain Name Systems are highly redundant. This redundancy is important to ensure that the root DNS service continues to be provided even if one of the DNS root servers fails. These servers are well maintained and fail rarely. However, on October 1st, the H instance of the root DNS servers maintained by the US Army failed.

Computer Networking course : part 2 (Application layer)

obo — Tue, 29 Sep 2009 08:01:49 +0000

First part

Second part

gmail is down, so what ?

obo — Thu, 03 Sep 2009 20:25:04 +0000

On September 1st, gmail was down for about 100 minutes. This is not the first time that gmail suffered from a failure and probably not the last one neither...