Your IP number, as determined by MLdonkey.
MLdonkey first look at IP numbers assigned to interfaces, avoiding localhost IPs. Then, if it manages to connect to eDonkey peers, it uses the source IP of the connected socket. (see commonOptions.ml, look for all instances of \"client_ip\") %%% That should be ok if your client is not behind some kind of address translation.
_-- It was suggested to use the HighID given by servers to determine the client_ip; But that trick only works for the eDonkey network..._ %%% _it seems to have been implemented, but it's experimental : enable use_server_id_
If you set force_client_ip to true, you can set client_ip to any value you want, overriding MLdonkey guess.