iron box: n.

[Unix/Internet] A special environment set up to trap a cracker logging in over remote connections long enough to be traced. May include a modified shell restricting the cracker's movements in unobvious ways, and ‘bait’ files designed to keep him interested and logged on. See also back door, firewall machine, Venus flytrap, and Clifford Stoll's account in The Cuckoo's Egg of how he made and used one (see the Bibliography in Appendix C). Compare padded cell, honey pot.