A user changes his password. It then performs a checksum on the resulting buffer and if it does not match the supplied checksum it discards the buffer and asks for the whole file to be sent. Two users change their passwords at the same time. If both datagrams are in the queue on the first pass, it will make one pass through the passwd file. If the second datagram does not arrive until after the first pass has started, an additional pass will be made before the ptmp file is flushed.
Someone runs vipw to change several passwd entries.
It reads the entire file in and does a line by line comparison, inserting entries into its transaction log for every line that differs. Gts file Get the specified file with a timestamp of 'ts' or later. This ensures that the file is loaded and starts the process of broadcasting the packets across the network. The client and sequence numbers are returned in the reply to distinguish the request that generated it. The specified UID must exist in the current passwd file.