This listing profiles the different headers generated by different newsgroup programs. By convention these fields must adhere to RFC-822 and RFC-1036 specifications although there is some leeway in the additional of new header fields. Wherever possible, example fields are given. This list was collected from a snapshot of select newsgroups on February 1, 1998.

Approved: (common)
Approved-By: (rare)

Used within moderated newsgroups to identify those messages that have been approved by the moderator. Typically this field contains the mailing address of the moderator to allow verification. The formatting is the same as the From: field. The two different fields are used identically

This field is for administrative use only by Newsgroup moderators. The posting is to be saved into a newsgroup archive. Typical use is for retaining discussion on starting or breaking up newsgroups by the moderators.

This field is generated by Microsoft Outlook Express to reference who posted the message and from what news server. The domain before the exclamation point is the NNTP server referred to by the NNTP-Posting-Host: field. The domain after the exclamation point is the NNTP host connection used by the originating server.

If someone wants to post a message to a newsgroup as well as send a copy via e-mail to someone, some news client software allows carbon copy field to perform this function. Its format must be a valid e-mail address. Also used to post newsgroup messages to dedicated list servers and moderators.

This field is where an author may add additional comments about the message to aid news server operators in handling this message in case of questions.

This is actually a variation of the COMMENT and CONTENT-TYPE fields. It is rarely used and was only seen once.

Used to indicate how the newsgroup message was created and posted.

This newsgroup posting field is a duplicate for Message-ID and is generated by some Usenet gateways.

This is the only header that begins with a lower case character. This specifies the size of the posting in number of bytes.

This field specifies the character format of the posting.

This is actually MIME information about the content of the newsgroup posting. It gives a pointer on how to handle its content. There are also hints as to how this message was posted.

This field is the date that the message was posted on the authors Usenet server.

Usually thrown in by news servers' operated by companies and educational groups to hold themselves blameless for anything that their users say on the newsgroups.

For local newsgroups, this field restricts how far a message is distributed. Examples are LOCAL=this news server only, WORLD=unlimited, US=United States only, NE=North East New England United States only. Also specific networks may be named to prevent the posting from crossing gateways.

This field contains an e-mail address to be used to report system errors. Used by a news server to indicate whom to contact for errors in the post. Also used to identify those responsible for maintaining the news server in case of abuse by a user.

Most of the time a news server will delete a posting after its own self-determined number of days. If this field specifies an earlier date then the message will be deleted sooner. This field has the same format as the standard Date field. This field is intended for time sensitive postings, and frequently updated postings such as INFO, FAQ's, and Nubie announcements.

This is a moderator control field to make a copy of the posting in the specified newsgroup. Typically used to force copies of an official posting into a public announcement newgroup.

The posting author's full E-Mail address. Be aware that although the RFC's specify the proper format for this field, in practice, there is little adherance to this specification. In addition, this is a user editable field so its actual appearance cannot always be predected.

This is a duplicate of the Reference: newsgroup header field. Where examples of this header field were used, the Reference field was used as well. Several examples were traced to Freenets and BBS's.

The Keyword field is a good idea that was never put into wide spread implementation. The intention is for the poster to specify a few key words that help describe what the posting is about. This way, users could search newsgroup postings quickly for their topic. In practice, this is too much work to ask most people to do and most newsgroup posters use it incorrectly. The AIR Newsreader version 3.X from SPRY, Inc. is the only news program that still generates this field.

This field lists the number of message lines after the header. The number is always a positive integer.

Another field to indicate that a copy of this message has been e-mailed to a particular address. Examples observed are for posting public messages to an individual user.

For postings that originated by e-mailing a mail to Usenet gateway, this field identifies whom to contact in case of problems or abuse.

This field is the unique identifier for each posting. It should never be duplicated within two years. In practice, since the code is based upon the date and time, it may never be duplicated.

This field is used to identify that the posting contains MIME information that can be processed. Such as attached files, enclosed HTML formatting, or anything that requires an external program to use.

This field identifies which newsgroups to post this message to.

When the originating news server delays passing on a new posting when it is first received, it may report the time and date that it was passed onto its host. The format is the same as the Date field.

This nearly standard field specifies what Usenet server originated this message. The X-NNTP-Posting-Host field was observed to be a duplicate of an existing NNTP-Posting-Host field and can be considered identical.

This field originates from the AirMail newsgroup proxy server. It is date that the e-mail was copied from mail server onto the Usenet server.

This field identifies the user account owned by the posting author. It is unique to mainframe systems and seems to be the Login username.

This field originates from the AirMail newsgroup proxy server. It identifies the gateway server used to move email to the newgroup.

A user editable field to allow posting authors to identify their affiliation.

Used by moderators to identify themselves when they post a moderated Usenet message in the name of someone else.

Used to as an alternative field to identify a moderator.

Indicates the sequence of Usenet servers that the posting took to get from the author to your server.

This field is typically found in moderated newsgroups.

Indicates that a posting has a different level of importance then normal. In all of the examples found, all were of first priority.

Used on certain Usenet servers to indicate when a posting was received by an author. The DATE field specifies when the author created the message, the Received field indicates when they posted it to the newsgroup.

This field indicates that this message is posted in reply to a previous existing article. The field specifies the original Message-ID field of all postings relevant to that thread.

This field is used to specify whom to reply to if there is a different e-mail address that they would rather receive mail.

Resent-Date: Thu, 29 Jan 1998 21:44:29 -0800 (PST)

In moderated newsgroups, this is the moderators mail address.

Generated by moderators of Usenet newsgroups.

Used by newsgroup moderators to reference List Servers through a newsgroup gateway.

Used by moderators to identify that they have post a message in a newsgroup on behalf of the user specified in the From field. In this way, the author of the post can take credit for what they wrote.

This field identifies the purpose of the posting and its topic. Replies to previously posted topics usually prefix the field data with the letters RE: to indicate that it is a reply.

Used to replace one posting with another. Typically used by moderators to replace an offensive or erroneous message with a correct one. The field entry identifies the Message-ID of the original posting that this new posting is to replace. The original posting is deleted.

Left over from some news and mail servers. Typically when a newsgroup posting was created for public reading on a newsgroup as well as sending to a particular user by e-mail.

This appears to originate from a Bulletin Board System's message conference. The field indicates how many times the posting was read before it was exported to the newsgroup.

Used to identify who administers a particular Usenet server. Direct complaints, and reports to this mail address. Typically used by larger ISP's as well as corporate offices.

A field that originates from DejaNews postings. The same as the Date field.

A security field that indicates that the posted message has been approved for a moderated newsgroup. Different newsgroup moderators use different parameters for each newsgroup.

This field is generated from DejaNews to indicate a verified mail address.

This field is generated by Usenet newsgroup moderator software.

Examples of this field originated from the Prodigy Online service. This appears to be a user account reference.

A field generated by the mail2news server.

This field is generated by the MAIL2NEWS gateway server to indicate when the article was forwarded from mail to the newsgroup. This field has also been used by moderators.

This field is generated by the FIDONET gateway server to indicate the SysOp of the originating BBS.

Generated by educational, ISP's, and service provider Usenet sites to receive abuse complaints about their users.

Used to automatically specify message encryption software used to encode the message.

This field appears to be generated by a Macintosh system to store a thumbnail picture of the author for use by their news software. The field routinely runs 64 characters long.

A field generated by the FIDONET gateway that indicates the Fidonet Zone of the BBS that generated this newsgroup post.

A field generated by the FIDONET gateway that indicates the name of the BBS that generated this newsgroup post as well as certain Fido information.

In case of replies, this field indicates the Fidonet path back to the author's BBS through the FIDONET Gateway. The zone is specified in the X-FTN-Domain field.

A field that indicates the Fidonet nodes of the BBS's that have seen this message prior to being sent through the FIDONET Gateway into the Usenet Newsgroup. These are the Hubs and Node numbers in Fidonet convention.

A field generated by the FIDONET gateway that indicates the name of the BBS software that generated this newsgroup post.

Used to indicate which FIDONET gateway was used to transfer the message into this Usenet newsgroup.

A unique field generated by the National Capital Freenet of Ottawa, Canada.

This field is generated when someone posts a Usenet message through DejaNews.

Used when someone posts a newsgroup message through Juno.

Used for moderated newsgroups run by a mail list server.

Generated by moderated newsgroup software for administrative purposes.

This field originates from bulletin board systems connected on the Internet. Typically Freenets.

This field is generated by bulletin board systems connected to the Internet. This field is duplicated by the From field.

This field is generated by an NNTP-FIDO gateway used for bulletin boards.

Indicates what version of mail software was used. It is functionally identical to the X-Newsreader field. Typically generated when an author posts their message through the MAIL2NEWS gateway.

Used to identify a moderated posting that originated from a list server.

An alternative field used to indicate the mail program used to send postings through mail to news gateways.

Indicates the encryption mode required for contacting the author. This field was only observed generated by Mozilla 3.01 for the Macintosh.

A moderated newsgroup that is controlled through a mailing list server uses this field to identify the mailing address of the original author of the message.

This field is created when a message posting was created in an incompatible format then what is required by a moderator.

This field originated from Microsoft Outlook Express as specified by the X-Newsreader field.

Used to hold just the message identification code from the Message-ID field.

Generated by Microsoft's Mail program to specify importance of this posting. Seems to be a duplicate of the Priority field. Typically generated when an author posts a message to a newsgroup through the MAIL2NEWS Usenet gateway server using Microsoft Mail.

This field originates from Netcom to indicate the date that their server received this message for posting.

Used by a custom news server to specify which newsgroup a message was originally posted to.

This field originates from mass-cross-posting spam software called AtomicPost.

This field is unique to the Ameol Usenet news reader out of the United Kingdom and is identical to X-Newsreader field.

This field is identical to the standard NNTP-Posting-Host except that the IP address is appended to the end of the host domain name.

This field is used as a security conformation on the origin of the message. It originates from educational institutions with a custom news server. Note the odd case of the field name.

This field specifies that a posting should be saved.

Originates from DejaNews. Identifies the IP address of the author of this posting.

A field generated by the AirNews proxy server. It appears to be identical to the Message-ID field and may be its original field before proxy.

Generated by Primenet and included on all postings that originates on their Usenet server.

This field is functionally identical to the X-Newsreader field.

This field contains identical information as the Date field.

Some educational and corporate Usenet servers generate this field.

Used by Internet service providers, online services, and major network hubs to let others know whom to contact in case one of their users is causing problems.

Used by moderators of newsgroups to address questions and complaints.

Generated by bulletin board systems that use an NNTP-QWK gateway.

This field identifies the original article number on your host Usenet server. The newsgroups specified should match the Newsgroup field.

Generated by some newsgroup moderator software that accepts e-mail postings to a list server.

Generated by custom Usenet Newsgroup moderating software to specify how to get in touch with the author of the posting. Usually the same as the From field but occasionally different when the source was through a List Server.

Generated by software that automatically moderates newsgroups by removing or allowing posts relevent to the specific newsgroup. This field identifies the operator of the Robot Moderator software.

Generated by the SCRM Usenet Newsgroup Robot Moderator software.

Only observed generated when an author posts a message through a mail to news gateway onto a moderated newsgroup. This field was always the same as the From field.

Generated by an E-Mail server AzStartNet and will appear in a Usenet newsgroup header if received through a Mail to News gateway.

From users of the Mindspring Usenet server.

Indicates that this is a moderated newsgroup and all postings should be submitted to this address for verification of content and then posting to the newsgroup.

Indicates that the origin computer was a Sun workstation. Identical to the Content-Type field.

Created by a Wildcat network using FIDONET or QWK networking to post their message.

Generated by secure newsgroup servers to identify all posting through their site.

This field is generated by Usenet newsgroup messages posted from the UltraNet Communications NNTP server.

Generated by moderator software that could not parse the date field. Seems to be more a diagnostic tag then anything functional. The problem appears to be that their parser is unable to handle the day of the week prefix common to these date formats.

Used as a way to identify a newsgroup moderator and their policies.

Used to specify the original e-mail address the post was carbon copied to. Used on Digital Equipment VAX gateways between Usenet and mail.

A unique field generated by the XS4ALL newsgroup server in the Netherlands. This field seems to indicate the time and date that the message was received from the user and exported to the Usenet.

A unique field generated by the XS4ALL newsgroup server in the Netherlands. This field seems to indicate the user mail address and the port that they connected through.