hello, I've already downloaded and installed this binary on my macbook pro. After that I type the command "ns" under the Terminal , it's successful to come the sign "%" . Thanks for your contribution. But today I try to add my own Agent file (.cc .h) into the ns-allinone-2.34 (locate at "/ ") and remake the ns-2.34, it doesn't work any more and "ns" command can also not be found under the terminal. Here is my steps: 1. add my (myagent.cc, myagent.h) file into /ns-allinone-2.34/ns-2.34/myfiles (the binaries seem that automatically installed under "/") 2. change the Makefile of ns-2.34, add the line "/myfiles/myagent.o" into OBJ_CC 3. To remake the ns-2.34 , I type the commands "make clean" and then "make" in terminal under /ns2-allinone-2.34/ns-2.34 Have you any ideas about this trouble? Because I installed and compiled successfully the NS2 in mac os 10.5.x before, and after the upgrading the system to 10.6.x, it doesn't work anymore and gives me a headache. Thank you again for your attention and reply. Anyway, this binary is a great job for mac users who would like simulate with ns2.