ihave

 $nntp->ihave(msgid[, message])

Informs the server that the client has an article whose ID is msgid. The optional argument message can be either an array of lines or a reference to an array. If message is specified, and the server wants a copy, it is sent, returning true on successful completion.

If message is not specified, then the message must be sent using the Net::Cmd datasend and dataend methods.