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udp-receiver

NAME

udp-receiver - receive files broadcast by udp-sender

SYNOPSIS

./udp-receiver [--file file] [--pipe pipe] [--portbase portbase] [--interface net-interface] [--log file] [--ttl time-to-live] [--mcast-rdv-address mcast-rdv-address] [--nokbd] [--exitWait milliseconds]

DESCRIPTION

"Udp-receiver" is used to receive files sent by "udp-sender" (for instance a disk image).

OPTIONS

Basic options

--file file

Writes received data to file. If this parameter is not supplied, received data is written to stdout instead.

--pipe command

Sends data through pipe after receiving it. This is useful for decompressing the data, or for filling in unused filesystem blocks that may have been stripped out by udp-sender. The command gets a direct handle on the output file or device, and thus may seek inside it, if needed. "Udpcast" itself also keeps a handle on the file, which is used for an informational progress display. The command's stdin is a pipe from udp-receiver. Example: "udp-receiver -p "gzip -dc""

--log file

Logs some stuff into file.

--nosync

Do not open target in synchronous mode. This is the default when writing to a file or a pipe.

--sync

Write to target in synchronous mode. This is the default when writing to a device (character or block)

--nokbd

Do not read start signal from keyboard, and do not display any message telling the user to press any key to start.

--start-timeout sec

receiver aborts at start if it doesn't see a sender within this many seconds. Furthermore, the sender needs to start transmission of data within this delay. Once transmission is started, the timeout no longer applies.

Networking options

--portbase portbase

Default ports to use for udpcast. Two ports are used: portbase and portbase+1 . Thus, Portbase must be even. Default is 9000. The same portbase must be specified for both "udp-sender" and "udp-receiver".

--interface interface

Network interface used to send out the data. Default is "eth0"

--ttl ttl

Time to live for connection request packet (by default connection request is broadcast to the LAN's broadcast address. If ttl is set, the connection request is multicast instead to 224.0.0.1 with the given ttl, which should enable udpcast to work between LANs. Not tested though.

--mcast-rdv-address address

Uses a non-standard multicast address for the control connection (which is used by the sender and receivers to ``find'' each other). This is not the address that is used to transfer the data. By default "mcast-rdv-address" is the Ethernet broadcast address if "ttl" is 1, and 224.0.0.1 otherwise. This setting should not be used except in very special situations, such as when 224.0.0.1 cannot be used for policy reasons.

--exit-wait milliseconds

When transmission is over, receiver will wait for this time after receiving the final REQACK. This is done in order to guard against loss of the final ACK. Is 500 milliseconds by default.

SEE ALSO

udp-sender

AUTHOR

Alain Knaff