@node nncp-ack
@cindex packet acknowledgement
@pindex nncp-ack
@section nncp-ack

@example
$ nncp-ack [options] NODE [PKT|rx]
@end example

Sent acknowledgement of successful @option{PKT} (Base32-encoded hash)
packet receipt. If @option{rx} is specified instead, then all
@option{NODE}'s existing @code{rx} packets will be acknowledged.

General workflow with acknowledgement is following, assuming that
Alice has some outbound packets for Bob:

@itemize

@item Transfer an encrypted packets, without deleting them locally:

@example
alice$ nncp-xfer -keep -tx -node bob /mnt/shared
@end example

@item On Bob's side retrieve those packets:

@example
bob$ nncp-xfer -rx /mnt/shared
@end example

That will also check if copied packets checksum is not mismatched.

@item Create ACK packets of received ones:

@example
bob$ nncp-ack alice rx
@end example

@item Send those newly created packets back to Alice:

@example
bob$ nncp-xfer -tx /mnt/shared
@end example

@item Get those acknowledgement packets and @ref{nncp-toss, toss} them:

@example
alice$ nncp-xfer -rx /mnt/shared
alice$ nncp-toss
@end example

Each ACK packet will remove kept corresponding outbound packets, because
Bob explicitly confirmed their receipt.

@end itemize

Similarly you can use it with @command{@ref{nncp-bundle}}, but do not
forget that by default it does not do checksumming of the packets, so
you should either use its @option{-check} option, or run
@command{@ref{nncp-check}} after.