500 - Command not found
501 - Wrong number of arguments
502 - Unauthorized request
503 - Already logged in
504 - Could not convert to character set
505 - Internal error
506 - Authentication error
507 - Command not expected
508 - No such authentication mechanism
509 - Malformed argument
510 - No such fnetnode
511 - No such fnet
512 - No such transfer
513 - Not supported for this fnet
514 - No such search
515 - Quota exceeded
516 - Duplicate recipient
517 - No such recipient
518 - Recipient not listening

600 - Chat receipt
601 - FN state change
602 - FN name change
603 - FN destroy
604 - FN create
605 - FN num peers change
610 - Transfer create
611 - Transfer state change
612 - Transfer nick change
613 - Transfer size change
614 - Transfer error update
615 - Transfer progress
616 - Transfer path change
617 - Transfer destroy
618 - Transfer hash update
620 - Search ETA change
621 - Search commit
622 - Search result
630 - Peer create
631 - Peer delete
632 - Peer change
640 - Client-to-client message