Question

list and describe Name resolution protocols .

Answer 1

Name resolution protocol is also knows as the Peer name resolution protocol.

PNRP was first mentioned during a presentation at a P2P conference in November 2001. It appeared in July 2003 in the Advanced Networking Pack for Windows XP, and was later included in the Service Pack 2 for Windows XP. PNRP 2.0 was introduced with Windows Vista and is available for download for Windows XP Service Pack 2 users.  PNRP 2.1 is included in Windows Vista SP1, Windows Server 2008 and Windows XP SP3. PNRP v2 is not available for Windows XP Professional x64 Edition or any edition of Windows Server 2003.

Windows Remote Assistance in Windows 7 uses PNRP, Teredo and IPv6 when connecting using the Easy Connect option.

PNRP Services:-

The PNRP is a distributed name resolution protocol allowing Internet hosts to publish "peer names" and corresponding IPv6 addresses and optionally other information. Other hosts can then resolve the peer name, retrieve the corresponding addresses and other information, and establish peer-to-peer connections.

With PNRP, peer names are composed of an "authority" and a "qualifier". The authority is identified by a secure hash of an associated public key, or by a place-holder (the number zero) if the peer name is "unsecured". The qualifier is a string, allowing an authority to have different peer names for different services.

If a peer name is secure, the PNRP name records are signed by the publishing authority, and can be verified using its public key. Unsecured peer names can be published by anybody, without possible verification.

Multiple entities can publish the same peer name. For example, if a peer name is associated with a group, any group member can publish addresses for the peer name.

Peer names are published and resolved within a specified scope. The scope can be a local link, a site (e.g. a campus), or the whole Internet.

PNRP and Distribute Hash Tables:-

Internally, PNRP uses an architecture similar to distributed hash table systems such as Chord or Pastry. The peer name is hashed to produce a 128-bit peer identifier, and a DHT-like algorithm is used to retrieve the location of the host publishing that identifier. There are however some significant differences.

DHT systems like Chord or Pastry store the indices of objects (hashes) at the node whose identifier is closest to the hash, and the routing algorithm is designed to find that node. In contrast, PNRP always store the hash on the node that publishes the identifier. A node will thus have as many entries in the routing system as the number of identifiers that it publishes. The PNRP design arguably trades increased security and robustness for higher routing cost.

Most DHT systems assume that only one node publishes a specific index. In contrast, PNRP allows multiple hosts to publish the same name. The internal index is in fact composed of the 128-bit hash of the peer name and a 128-bit location identifier, derived from an IPv6 address of the node.

PNRP does not use a routing table, but rather a cache of PNRP entries. New cache entries are acquired as a side effect of ongoing traffic. The cache maintenance algorithm ensures that each node maintains adequate knowledge of the "cloud". It is designed to ensure that the time to resolve a request varies as the logarithm of the size of the cloud.

In other words or in simple words you can aslo read this if you have doubt on the above one.

The Peer Name Resolution Protocol (PNRPsvc) service enables peer name resolution over the Internet without using a server. If this service is disabled, some peer-to-peer and collaborative applications may not function. This protocol enables the naming of computers and services without relying on a DNS server. This allows for flexible, informal, temporary networks of nearby computers for collaboration, data sharing, and data storage.

Security in peer-to-peer networks is difficult to establish. If computers in your organization are allowed to connect to peer-to-peer networks, a security policy about the types of information that is shared and the types of peer-to-peer networks that are compliant with your policy should be explicitly designed and communicated to your users. This helps users make decisions about which peer-to-peer networks they can trust.

A trusted peer-to-peer network should meet the following industry standards for establishing trust:

• Uses a trusted authentication method to identify the network and its users. Your security policy should identify which form of authentication is the minimally acceptable method.
• Supports different authorization levels to allow for control over who shares information by using the network.
• Supports encrypted data transmission so that when users collaborate over this network, their information is not as susceptible to capture by unauthorized users.
• Provides some form of data-integrity checking, such as digital signatures, to ensure that the data was not modified in transit.

This service is installed by default and its startup type is Manual.

When the Peer Name Resolution Protocol service is started in its default configuration, it logs on by using the Local Service account.

The Peer Name Resolution Protocol service is dependent upon the following system component:

• Peer Networking Identity Manager

The following system components are dependent upon the Peer Name Resolution Protocol service:

• Peer Networking Grouping
• PNRP Machine Name Publication Service

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