RFC Abstracts
RFC0846 - Who talks TCP? - survey of 22 February 1983
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 18-Feb-83. The tests were run on 22-Feb-83 from ISI-VAXA.ARPA.
RFC0845 - Who talks TCP? - survey of 15 February 1983
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 3-Feb-83. The tests were run on 15-Feb-83 from ISI-VAXA.ARPA.
RFC0844 - Who talks ICMP, too? - Survey of 18 February 1983
This survey determines how many hosts are able to respond to TELENET connections from a user at a class C site. This requires, in addition to IP and TCP, participation in gateway routing via ICMP and handling of Class C addresses. The list of hosts was taken from RFC 843, extracting only those hosts which are listed there as accepting TELNET connection. The tests were run on 18-Feb-83.
RFC0843 - Who talks TCP? - survey of 8 February 83
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 3-Feb-83. The tests were run on 8-Feb-83 and on 9-Feb-83 from ISI-VAXA.ARPA.
RFC0842 - Who talks TCP? - survey of 1 February 83
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 28-Jan-83. The tests were run on 1-Feb-83 and on 2-Feb-83 ISI-VAXA.ARPA.
RFC0841 - Specification for message format for Computer Based Message Systems
This RFC is FIPS 98. The purpose of distributing this document as an RFC is to make it easily accessible to the ARPA research community. This RFC does not specify a standard for the ARPA Internet. Obsoletes RFC 806.
RFC0840 - Official protocols
This RFC has been revised, see RFC 880.
RFC0839 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 31-Dec-82. The tests were run on 25-Jan-83.
RFC0838 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 31-Dec-82. The tests were run on 18-Jan-83.
RFC0837 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 31-Dec-82. The tests were run on 11-Jan-83.
RFC0836 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 20-Dec-82. The tests were run on 4-Jan-83 through 5-Jan-83.
RFC0835 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 28-Dec-82 through 5-Jan-83.
RFC0834 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 22-Dec-82.
RFC0833 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 14-Dec-82.
RFC0832 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 7-Dec-82.
RFC0831 - Backup access to the European side of SATNET
The purpose of this RFC is to focus discussion on a particular Internet problem: a backup path for software maintenance of the European sector of the Internet, for use when SATNET is partitioned. We propose a mechanism, based upon the Source Routing option of IP, to reach European Internet sites via the VAN Gateway and UCL. This proposal is not intended as a standard at this time.
RFC0830 - Distributed system for Internet name service
This RFC proposes a distributed name service for DARPA Internet. Its purpose is to focus discussion on the subject. It is hoped that a general consensus will emerge leading eventually to the adoption of standards.
RFC0829 - Packet satellite technology reference sources
This RFC describes briefly the packet satellite technology developed by the Defense Advanced Research Projects Agency and several other participating organizations in the U.K. and Norway and provides a bibliography of relevant papers for researchers interested in experimental and operational experience with this dynamic satellite-sharing technique.
RFC0828 - Data communications: IFIP's international "network" of experts
This RFC is distributed to inform the ARPA Internet community of the activities of the IFIP technical committee on Data Communications, and to encourage participation in those activities.
RFC0827 - Exterior Gateway Protocol (EGP)
This RFC is proposed to establish a standard for Gateway to Gateway procedures that allow the Gateways to be mutually suspicious. This document is a DRAFT for that standard. Your comments are strongly encouraged.
RFC0826 - An Ethernet Address Resolution Protocol: Or Converting Network Protocol Addresses to 48.bit Ethernet Address for Transmission on Ethernet Hardware
The purpose of this RFC is to present a method of Converting Protocol Addresses (e.g., IP addresses) to Local Network Addresses (e.g., Ethernet addresses). This is an issue of general concern in the ARPA Internet Community at this time. The method proposed here is presented for your consideration and comment. This is not the specification of an Internet Standard.
RFC0825 - Request for comments on Requests For Comments
This RFC is intended to clarify the status of RFCs and to provide some guidance for the authors of RFCs in the future. It is in a sense a specification for RFCs.
RFC0824 - CRONUS Virtual Local Network
The purpose of this note is to describe the CRONUS Virtual Local Network, especially the addressing related features. These features include a method for mapping between Internet Addresses and Local Network addresses. This is a topic of current concern in the ARPA Internet community. This note is intended to stimulate discussion. This is not a specification of an Internet Standard.
RFC0823 - DARPA Internet gateway
This RFC is a status report on the Internet Gateway developed by BBN. It describes the Internet Gateway as of September 1982. This memo presents detailed descriptions of message formats and gateway procedures, however, this is not an implementation specification, and such details are subject to change.
RFC0822 - STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES
This document revises the specifications in RFC 733, in order to serve the needs of the larger and more complex ARPA Internet. Some of RFC 733's features failed to gain adequate acceptance. In order to simplify the standard and the software that follows it, these features have been removed. A different addressing scheme is used, to handle the case of internetwork mail; and the concept of re-transmission has been introduced. Obsoletes RFC 733, NIC 41952.
RFC0821 - Simple Mail Transfer Protocol
The objective of Simple Mail Transfer Protocol (SMTP) is to transfer mail reliably and efficiently. SMTP is independent of the particular transmission subsystem and requires only a reliable ordered data stream channel. Obsoletes RFC 788, 780, and 772.
RFC0820 - Assigned numbers
This RFC is an old version, see RFC 870.
RFC0819 - The Domain Naming Convention for Internet User Applications
This RFC is an attempt to clarify the generalization of the Domain Naming Convention, the Internet Naming Convention, and to explore the implications of its adoption for Internet name service and user applications.
RFC0818 - Remote User Telnet service
This RFC is the specification of an application protocol. Any host that implements this application level service must follow this protocol.
RFC0817 - Modularity and efficiency in protocol implementation
This RFC will discuss some of the commonly encountered reasons why protocol implementations seem to run slowly.
RFC0816 - Fault isolation and recovery
This RFC describes the portion of fault isolation and recovery which is the responsibility of the host.
RFC0815 - IP datagram reassembly algorithms
This RFC describes an alternate approach of dealing with reassembly which reduces the bookkeeping problem to a minimum, and requires only one buffer for storage equal in size to the final datagram being reassembled, which can reassemble a datagram from any number of fragments arriving in any order with any possible pattern of overlap and duplication, and which is appropriate for almost any sort of operating system.
RFC0814 - Name, addresses, ports, and routes
This RFC gives suggestions and guidance for the design of the tables and algorithms necessary to keep track of these various sorts of identifiers inside a host implementation of TCP/IP.
RFC0813 - Window and Acknowledgement Strategy in TCP
This RFC describes implementation strategies to deal with two mechanisms in TCP, the window and the acknowledgement. It also presents a particular set of algorithms which have received testing in the field, and which appear to work properly with each other. With more experience, these algorithms may become part of the formal specification, until such time their use is recommended.
RFC0812 - NICNAME/WHOIS
This RFC gives a description of what the NICNAME/WHOIS Server is and how to access it. This server together with the corresponding Identification Data Base provides online directory look-up equivalent to the ARPANET Directory.
RFC0811 - Hostnames Server
This RFC gives a description of what the Hostnames Server is and how to access it. The function of this particular server is to deliver machine-readable name/address information describing networks, gateways, hosts, and eventually domains, within the internet environment.
RFC0810 - DoD Internet host table specification
This RFC specifies a new host table format applicable to both ARPANET and Internet needs. In addition to host name to host address translation and selected protocol information, we have also included network and gateway name to address correspondence, and host operating system information. This RFC obsoletes the host table described in RFC 608.
RFC0809 - UCL facsimile system
This RFC describes the features of the computerised facsimile system developed in the Department of Computer Science at UCL. First its functions are considered and the related experimental work are reported. Then the disciplines for system design are discussed. Finally, the implementation of the system are described, while detailed description are given as appendices.
RFC0808 - Summary of computer mail services meeting held at BBN on 10 January 1979
This RFC is a very belated attempt to document a meeting that was held three years earlier to discuss the state of computer mail in the ARPA community and to reach some conclusions to guide the further development of computer mail systems such that a coherent total mail service would continue to be provided.
RFC0807 - Multimedia mail meeting notes
This RFC consists of notes from a meeting held at USC Information Sciences Institute on the 12th of January to discuss common interests in multimedia computer mail issues and to agree on some specific initial experiments.
RFC0806 - Proposed Federal Information Processing Standard: Specification for message format for computer based message systems
This RFC deals with Computer Based Message systems which provides a basis for interaction between different CBMS by defining the format of messages passed between them. This RFC is replaced by RFC 841.
RFC0805 - Computer mail meeting notes
This RFC consists of notes from a meeting that was held at USC Information Sciences Institute on 11 January 1982, to discuss addressing issues in computer mail. The major conclusion reached at the meeting is to extend the "username@hostname" mailbox format to "username@host.domain", where the domain itself can be further strutured.
RFC0804 - CCITT draft recommendation T.4
This is the CCITT standard for group 3 facsimile encoding. This is useful for data compression of bit map data.
RFC0803 - Dacom 450/500 facsimile data transcoding
The first part of this RFC describes in detail the Dacom 450 data compression algorithms and is an update and correction to an earlier memorandum. The second part of this RFC describes briefly the Dacom 500 data compression algorithm as used by the INTELPOST electronic-mail network under development by the US Postal Service and several foreign administrators.
RFC0802 - ARPANET 1822L Host Access Protocol
This document proposed two major changes to the current ARPANET host access protocol. The first change will allow hosts to use logical addressing (i.e., host addresses that are independent of their physical location on the ARPANET) to communicate with each other, and the second will allow a host to shorten the amount of time that it may be blocked by its IMP after it presents a message to the network (currently, the IMP can block further input from a host for up to 15 seconds). See RFCs 852 and 851.
RFC0801 - NCP/TCP transition plan
This RFC discusses the conversion of hosts from NCP to TCP. And making available the principle services: Telnet, File Transfer, and Mail. These protocols allow all hosts in the ARPA community to share a common interprocess communication environment.
RFC0800 - Request For Comments summary notes: 700-799
This RFC is a slightly annotated list of the 100 RFCs from RFC 700 through RFC 799. This is a status report on these RFCs.
RFC0698 - Telnet extended ASCII option
Describes an option to allow transmission of a special kind of extended ASCII used at the Stanford AI and MIT AI Labs.
RFC0697 - CWD command of FTP
Discusses FTP login access to "files only" directories.
RFC0696 - Comments on the IMP/Host and Host/IMP Protocol changes
Observations on current international standards recommendations from IFIP working group 6.1; see also RFCs 692, 690, 687.
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 18-Feb-83. The tests were run on 22-Feb-83 from ISI-VAXA.ARPA.
RFC0845 - Who talks TCP? - survey of 15 February 1983
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 3-Feb-83. The tests were run on 15-Feb-83 from ISI-VAXA.ARPA.
RFC0844 - Who talks ICMP, too? - Survey of 18 February 1983
This survey determines how many hosts are able to respond to TELENET connections from a user at a class C site. This requires, in addition to IP and TCP, participation in gateway routing via ICMP and handling of Class C addresses. The list of hosts was taken from RFC 843, extracting only those hosts which are listed there as accepting TELNET connection. The tests were run on 18-Feb-83.
RFC0843 - Who talks TCP? - survey of 8 February 83
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 3-Feb-83. The tests were run on 8-Feb-83 and on 9-Feb-83 from ISI-VAXA.ARPA.
RFC0842 - Who talks TCP? - survey of 1 February 83
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 28-Jan-83. The tests were run on 1-Feb-83 and on 2-Feb-83 ISI-VAXA.ARPA.
RFC0841 - Specification for message format for Computer Based Message Systems
This RFC is FIPS 98. The purpose of distributing this document as an RFC is to make it easily accessible to the ARPA research community. This RFC does not specify a standard for the ARPA Internet. Obsoletes RFC 806.
RFC0840 - Official protocols
This RFC has been revised, see RFC 880.
RFC0839 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 31-Dec-82. The tests were run on 25-Jan-83.
RFC0838 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 31-Dec-82. The tests were run on 18-Jan-83.
RFC0837 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 31-Dec-82. The tests were run on 11-Jan-83.
RFC0836 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 20-Dec-82. The tests were run on 4-Jan-83 through 5-Jan-83.
RFC0835 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 28-Dec-82 through 5-Jan-83.
RFC0834 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 22-Dec-82.
RFC0833 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 14-Dec-82.
RFC0832 - Who talks TCP?
This RFC is a survey of hosts to identify the implementation status of Telnet, FTP, and Mail on TCP. The list of hosts was taken from the NIC hostname table of 2-Dec-82. The tests were run on 7-Dec-82.
RFC0831 - Backup access to the European side of SATNET
The purpose of this RFC is to focus discussion on a particular Internet problem: a backup path for software maintenance of the European sector of the Internet, for use when SATNET is partitioned. We propose a mechanism, based upon the Source Routing option of IP, to reach European Internet sites via the VAN Gateway and UCL. This proposal is not intended as a standard at this time.
RFC0830 - Distributed system for Internet name service
This RFC proposes a distributed name service for DARPA Internet. Its purpose is to focus discussion on the subject. It is hoped that a general consensus will emerge leading eventually to the adoption of standards.
RFC0829 - Packet satellite technology reference sources
This RFC describes briefly the packet satellite technology developed by the Defense Advanced Research Projects Agency and several other participating organizations in the U.K. and Norway and provides a bibliography of relevant papers for researchers interested in experimental and operational experience with this dynamic satellite-sharing technique.
RFC0828 - Data communications: IFIP's international "network" of experts
This RFC is distributed to inform the ARPA Internet community of the activities of the IFIP technical committee on Data Communications, and to encourage participation in those activities.
RFC0827 - Exterior Gateway Protocol (EGP)
This RFC is proposed to establish a standard for Gateway to Gateway procedures that allow the Gateways to be mutually suspicious. This document is a DRAFT for that standard. Your comments are strongly encouraged.
RFC0826 - An Ethernet Address Resolution Protocol: Or Converting Network Protocol Addresses to 48.bit Ethernet Address for Transmission on Ethernet Hardware
The purpose of this RFC is to present a method of Converting Protocol Addresses (e.g., IP addresses) to Local Network Addresses (e.g., Ethernet addresses). This is an issue of general concern in the ARPA Internet Community at this time. The method proposed here is presented for your consideration and comment. This is not the specification of an Internet Standard.
RFC0825 - Request for comments on Requests For Comments
This RFC is intended to clarify the status of RFCs and to provide some guidance for the authors of RFCs in the future. It is in a sense a specification for RFCs.
RFC0824 - CRONUS Virtual Local Network
The purpose of this note is to describe the CRONUS Virtual Local Network, especially the addressing related features. These features include a method for mapping between Internet Addresses and Local Network addresses. This is a topic of current concern in the ARPA Internet community. This note is intended to stimulate discussion. This is not a specification of an Internet Standard.
RFC0823 - DARPA Internet gateway
This RFC is a status report on the Internet Gateway developed by BBN. It describes the Internet Gateway as of September 1982. This memo presents detailed descriptions of message formats and gateway procedures, however, this is not an implementation specification, and such details are subject to change.
RFC0822 - STANDARD FOR THE FORMAT OF ARPA INTERNET TEXT MESSAGES
This document revises the specifications in RFC 733, in order to serve the needs of the larger and more complex ARPA Internet. Some of RFC 733's features failed to gain adequate acceptance. In order to simplify the standard and the software that follows it, these features have been removed. A different addressing scheme is used, to handle the case of internetwork mail; and the concept of re-transmission has been introduced. Obsoletes RFC 733, NIC 41952.
RFC0821 - Simple Mail Transfer Protocol
The objective of Simple Mail Transfer Protocol (SMTP) is to transfer mail reliably and efficiently. SMTP is independent of the particular transmission subsystem and requires only a reliable ordered data stream channel. Obsoletes RFC 788, 780, and 772.
RFC0820 - Assigned numbers
This RFC is an old version, see RFC 870.
RFC0819 - The Domain Naming Convention for Internet User Applications
This RFC is an attempt to clarify the generalization of the Domain Naming Convention, the Internet Naming Convention, and to explore the implications of its adoption for Internet name service and user applications.
RFC0818 - Remote User Telnet service
This RFC is the specification of an application protocol. Any host that implements this application level service must follow this protocol.
RFC0817 - Modularity and efficiency in protocol implementation
This RFC will discuss some of the commonly encountered reasons why protocol implementations seem to run slowly.
RFC0816 - Fault isolation and recovery
This RFC describes the portion of fault isolation and recovery which is the responsibility of the host.
RFC0815 - IP datagram reassembly algorithms
This RFC describes an alternate approach of dealing with reassembly which reduces the bookkeeping problem to a minimum, and requires only one buffer for storage equal in size to the final datagram being reassembled, which can reassemble a datagram from any number of fragments arriving in any order with any possible pattern of overlap and duplication, and which is appropriate for almost any sort of operating system.
RFC0814 - Name, addresses, ports, and routes
This RFC gives suggestions and guidance for the design of the tables and algorithms necessary to keep track of these various sorts of identifiers inside a host implementation of TCP/IP.
RFC0813 - Window and Acknowledgement Strategy in TCP
This RFC describes implementation strategies to deal with two mechanisms in TCP, the window and the acknowledgement. It also presents a particular set of algorithms which have received testing in the field, and which appear to work properly with each other. With more experience, these algorithms may become part of the formal specification, until such time their use is recommended.
RFC0812 - NICNAME/WHOIS
This RFC gives a description of what the NICNAME/WHOIS Server is and how to access it. This server together with the corresponding Identification Data Base provides online directory look-up equivalent to the ARPANET Directory.
RFC0811 - Hostnames Server
This RFC gives a description of what the Hostnames Server is and how to access it. The function of this particular server is to deliver machine-readable name/address information describing networks, gateways, hosts, and eventually domains, within the internet environment.
RFC0810 - DoD Internet host table specification
This RFC specifies a new host table format applicable to both ARPANET and Internet needs. In addition to host name to host address translation and selected protocol information, we have also included network and gateway name to address correspondence, and host operating system information. This RFC obsoletes the host table described in RFC 608.
RFC0809 - UCL facsimile system
This RFC describes the features of the computerised facsimile system developed in the Department of Computer Science at UCL. First its functions are considered and the related experimental work are reported. Then the disciplines for system design are discussed. Finally, the implementation of the system are described, while detailed description are given as appendices.
RFC0808 - Summary of computer mail services meeting held at BBN on 10 January 1979
This RFC is a very belated attempt to document a meeting that was held three years earlier to discuss the state of computer mail in the ARPA community and to reach some conclusions to guide the further development of computer mail systems such that a coherent total mail service would continue to be provided.
RFC0807 - Multimedia mail meeting notes
This RFC consists of notes from a meeting held at USC Information Sciences Institute on the 12th of January to discuss common interests in multimedia computer mail issues and to agree on some specific initial experiments.
RFC0806 - Proposed Federal Information Processing Standard: Specification for message format for computer based message systems
This RFC deals with Computer Based Message systems which provides a basis for interaction between different CBMS by defining the format of messages passed between them. This RFC is replaced by RFC 841.
RFC0805 - Computer mail meeting notes
This RFC consists of notes from a meeting that was held at USC Information Sciences Institute on 11 January 1982, to discuss addressing issues in computer mail. The major conclusion reached at the meeting is to extend the "username@hostname" mailbox format to "username@host.domain", where the domain itself can be further strutured.
RFC0804 - CCITT draft recommendation T.4
This is the CCITT standard for group 3 facsimile encoding. This is useful for data compression of bit map data.
RFC0803 - Dacom 450/500 facsimile data transcoding
The first part of this RFC describes in detail the Dacom 450 data compression algorithms and is an update and correction to an earlier memorandum. The second part of this RFC describes briefly the Dacom 500 data compression algorithm as used by the INTELPOST electronic-mail network under development by the US Postal Service and several foreign administrators.
RFC0802 - ARPANET 1822L Host Access Protocol
This document proposed two major changes to the current ARPANET host access protocol. The first change will allow hosts to use logical addressing (i.e., host addresses that are independent of their physical location on the ARPANET) to communicate with each other, and the second will allow a host to shorten the amount of time that it may be blocked by its IMP after it presents a message to the network (currently, the IMP can block further input from a host for up to 15 seconds). See RFCs 852 and 851.
RFC0801 - NCP/TCP transition plan
This RFC discusses the conversion of hosts from NCP to TCP. And making available the principle services: Telnet, File Transfer, and Mail. These protocols allow all hosts in the ARPA community to share a common interprocess communication environment.
RFC0800 - Request For Comments summary notes: 700-799
This RFC is a slightly annotated list of the 100 RFCs from RFC 700 through RFC 799. This is a status report on these RFCs.
RFC0698 - Telnet extended ASCII option
Describes an option to allow transmission of a special kind of extended ASCII used at the Stanford AI and MIT AI Labs.
RFC0697 - CWD command of FTP
Discusses FTP login access to "files only" directories.
RFC0696 - Comments on the IMP/Host and Host/IMP Protocol changes
Observations on current international standards recommendations from IFIP working group 6.1; see also RFCs 692, 690, 687.