It looks like Ircus have been using a fully exposed application
to access their flags! Look at this traffic I captured.
I can't seem to get it to work, though... can you help me
get the flag for this very challenge?

NOTE: During normal operation, directly connecting to flagserver using nc should give some nonprintable characters like 锟斤拷. If instead you receive nothing, please let us know.

得到的flag使用NSSCTF{}格式提交。