npush, npoll - copy files over TCP
npush [-b] [files...]
npush and npoll are tools to quickly copy files over an IP LAN. npush will send
UDP multicast/broadcast packets to advertise that it is willing to send files,
npoll will look for these UDP packets and then connect to the sending machine.
The advantage is that you don't have to type the name of the machine that you
want to send data to, and you don't have to type the name of the server.
Optionally, you can tell npoll the name of the server. This is useful if the
server is not in the same LAN.
If you do not give npush any arguments, it will copy stdin over the network.
npoll will in this case output the data to stdout. To make this work in pipes,
the diagnostic messages are now output on stderr.
npush will use TCP port 8002 for its connections and for the UDP packets. npush
will try to advertise using IPv6 multicast, but it will fall back to IPv4
multicast and IPv4 broadcast (which was the only option before version 1.0).
Use the -b
option to npush to make sure that clients before version 1.0
can see the advertisements.
npush will call tar only after it has opened the connection. If you forgot to
specify and files or tried to send nonexistant files, tar will spew out error
messages. The peer will see no error messages!
No error detection, error recovery or even decent error messages.
The broadcast packets always go out over the network interface with the default
route. This means that your PPP dialin server will npush the broadcast packets
to the PPP interface. You can fix this by setting a static route for
destination 255.255.255.255 to the LAN interface.
Some routers are stupid enough to forward the broadcast packets.
Felix 'Fefe' von Leitner <email@example.com>