The 13 root servers are a network of authoritative DNS (Domain Name System) servers critical for the internet's function, translating domain names into IP addresses. While there are only 13 named root servers (A through M), each of these operates multiple physical servers geographically distributed to improve performance and resilience.
Here's a breakdown of each root server, including its letter designation, IPv4 address, and the organization responsible for its operation:
| Letter | IPv4 Address | Operator |
|---|---|---|
| A | 198.41.0.4 | VeriSign |
| B | 170.247.170.2 | University of Southern California (ISI) |
| C | 192.33.4.12 | Cogent Communications |
| D | 199.7.91.13 | University of Maryland |
| E | 192.203.230.10 | NASA (Ames Research Center) |
| F | 192.5.5.241 | Internet Systems Consortium, Inc. |
| G | 192.112.36.4 | U.S. Department of Defense (NIC) |
| H | 128.63.2.53 | U.S. Army Research Lab |
| I | 192.36.148.17 | Netnod |
| J | 192.58.128.30 | VeriSign |
| K | 193.0.14.129 | RIPE NCC |
| L | 199.7.83.42 | ICANN |
| M | 202.12.27.33 | WIDE Project |
Key Points About Root Servers:
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Hierarchical DNS Structure: Root servers sit at the top of the DNS hierarchy. When a DNS resolver doesn't know the IP address for a domain, it starts by querying a root server.
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Anycast: Each lettered root server utilizes anycast addressing. This means multiple servers around the world share the same IP address. When a request is made, it's routed to the physically closest server, improving response times and providing redundancy.
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IPv6 Support: All root servers also support IPv6 addressing.
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Importance of Redundancy: The distributed nature of the root server system, with multiple instances of each server located globally, is crucial for maintaining the internet's stability and resilience. If one server fails, others can still respond to DNS queries.
In summary, the 13 root servers (A through M) are a vital part of the internet infrastructure, providing the initial point of contact for resolving domain names to IP addresses, and their distributed nature ensures high availability and performance.
