Hi Okech, JM Okech wrote:
Sorry Michuki, Listers, Just wondering .... from the document that you directed us together with the content of your mail it appears like we only have 12 root servers. My undersstanding that we have 13 root servers (interms of the allowable IP address) kindly clarify this....
There are 13 noted with letters A - M unless your page did not load completely please check and confirm. The limitation was as a result of the maximum DNS UDP packet size. The size set at 512bytes therefore has a limit on the amount of information that can be carried at any given time. Therefore using a short naming format "a.root-servers.net" plus the IPv4 address space it was only possible to fit in 13 of them. This has since changed. With the introduction of IPv6 glue for the Root-Servers and soon the DNSSEC information, there was need for a review of this limitation. EDNS0 allows DNS to pass through packets beyond 512bytes. However due to legacy systems and installations it does not work very well as these systems tend to block or drop DNS packets beyond 512bytes. The Wikipedia explanation for EDNS0 should give you the finer details of how it works. http://en.wikipedia.org/wiki/Extension_mechanisms_for_DNS Regards, Michuki.