DCC
DCC is a protocol that allows IRC clients to transfer files, and open a special
kind of chat sessions.
The File Send options can be used to optimize the transfer speed. The larger the
block the larger the transfer.
The protocol options "Binary" and "MacBinary" are described
in the DCC chapter. MacBinary should be used to transfer Macintosh files (that
have resources etc.) to another Mac. Binary should be used when sending to a PC.
This option only governs DCC that are started by dragging a file onto a nick in
the userlist.
Normal DCC transfers will bring up a file select dialog where you can set this
option on a transfer by transfer basis.
If a previous DCC receive failed because the connection was lost, Snak can often
resume the transfer at the point it was stopped. This is the resume option in
the group box.
NAT routers and AirPort
If you are on an AirPort network or behind a NAT router, you cannot receive DCC
transfers unless the NAT options are set up correctly. When you receive a file
via DCC, your machine is actually listening for a connection from the remote machine.
This listen happens on a port that you have informed the remote machine about
in the DCC accept message. Unfortunately a NAT setup hides your machine and its
port behind a public face (the public IP address), and the IP address of your
machine is not the one that the remote machine has access to.
Therefore when Snak sends out the DCC accept it needs to inform the remote machine
about the public IP address. That is the purpose of the "IP Address"
check box.
Snak will attempt to automatically determine this address if the "Auto configure"
option is turned on.
The second step in making Snak work from behind a NAT router is to restrict the
port range that it uses, so that the NAT router can route a well defined range
of ports on to the machine that is running Snak.
The third step is the actual configuration of the NAT router or AirPort network
to pass these ports on to the machine that is running Snak. That subject is impossible
to cover here because there are so many different systems.
DCC
