When a newsgroup is deleted on an NNTP server, the following technical process takes place:
1. The server removes the newsgroup from its active newsgroup list and marks it as deleted.
1. The server notifies other NNTP servers of the deletion by sending a control message called a cancel message to remove the group from their active newsgroup list.
1. The server also sends a cancel message to its own servers and clients that have subscribed to the deleted newsgroup to inform them of the deletion.
1. The messages in the deleted newsgroup are not physically deleted from the server immediately but are retained until the server’s expiration process removes them.
1. The server maintains a record of the deleted newsgroup in its history files, which contain a log of all the messages posted to the newsgroup.
1. Clients and servers that attempt to access the deleted newsgroup receive an error message and are unable to access the group.
1. If necessary, the server administrator can restore the deleted newsgroup by adding it back to the active newsgroup list and updating the server’s history files.
Overall, managing deleted newsgroups involves removing them from the active newsgroup list, notifying other servers and clients of the deletion, retaining message retention until expiration, and maintaining a record of the deleted newsgroup in the server’s history files.
