3.4. The IHAVE command

3.4.1. IHAVE

   IHAVE <messageid>

The IHAVE command informs the server that the client has an article whose id is <messageid>. If the server desires a copy of that article, it will return a response instructing the client to send the entire article. If the server does not want the article (if, for example, the server already has a copy of it), a response indicating that the article is not wanted will be returned.

If transmission of the article is requested, the client should send the entire article, including header and body, in the manner specified for text transmission from the server. A response code indicating success or failure of the transferral of the article will be returned.

This function differs from the POST command in that it is intended for use in transferring already-posted articles between hosts. Normally it will not be used when the client is a personal newsreading program. In particular, this function will invoke the server's news posting program with the appropriate settings (flags, options, etc) to indicate that the forthcoming article is being forwarded from another host.

The server may, however, elect not to post or forward the article if after further examination of the article it deems it inappropriate to do so. The 436 or 437 error codes may be returned as appropriate to the situation.

Reasons for such subsequent rejection of an article may include such problems as inappropriate newsgroups or distributions, disk space limitations, article lengths, garbled headers, and the like. These are typically restrictions enforced by the server host's news software and not necessarily the NNTP server itself.

3.4.2. Responses

   235 article transferred ok
   335 send article to be transferred.  End with <CR-LF>.<CR-LF>
   435 article not wanted - do not send it
   436 transfer failed - try again later
   437 article rejected - do not try again

An implementation note:

Because some host news posting software may not be able to decide immediately that an article is inappropriate for posting or forwarding, it is acceptable to acknowledge the successful transfer of the article and to later silently discard it. Thus it is permitted to return the 235 acknowledgement code and later discard the received article. This is not a fully satisfactory solution to the problem. Perhaps some implementations will wish to send mail to the author of the article in certain of these cases.