F Root

One of the 13 DNS root nodes of the Internet

ISC operates the “F” root domain server, one of the 13 Internet root name servers known as A-root through M-root. We have operated F-Root for IANA since 1994. The Root Server Technical Operations Association maintains a map that shows the location of all of the world’s root name servers. Over 125 of them are F Roots, operated by ISC.


If you are perplexed that over 125 (the number of F-root servers) is greater than 13 (the number of root name servers), you can read about the “anycast” scheme used to make the servers collectively behave as one server. F-root answers queries over IPv4 on, and over IPv6 on 2001:500:2f::f using a hierarchical anycast technique and BIND 9 software. Network operators can improve their access to the F Root Nameserver, and hence the reliability of the DNS in general, by peering with ISC at the exchange points where we maintain a presence.


We have almost 3,000 F-root peers. For information about peering with ISC, see our Peering Information Page.

Our Commitment to F-Root

On January 4th, 2008, ISC became the first root server operator to sign a Mutual Responsibilities Agreement with ICANN, which identifies mutual responsibilities and is another step to enhance Internet stability.


Below is a map showing the locations of F-root nodes worldwide. For more information and resources about F-Root, such as locations and identifying which F-root is providing service to you, visit our F-Root Resources Page.

Last modified: November 30, 2017 at 12:55 pm