Hello Tuhin Kanti Sharma, You are probably trying to use NS on a linux server with ssh. Am I wrong? Anyway, typing the following commands in your console should help you a lot: export DISPLAY = localhost:0
and if you are using ssh, please use the option -Y after having set the DISPLAY variable with the previous command, for example:: ssh -Y -l mydistantlogin mydistantcomputername Mit freundlichen Grüßen, with kind regards, cordialement, ---------------------------------------------------------------------- Gilles BERTRAND Institut National des Télécommunications (GET)- Universität Stuttgart http://raimizou.com/GB_online/pages/network_simulator.php ---------------------------------------------------------------------- Tuhin Kanti Sharma a écrit : >hi, >I m getting this error: >$ nam MySnoop.nam >nam: no display name and no $DISPLAY environment variable > >when I try to run nam on cygwin.if ne1 can hlp I would be obliged. > >Tuhin Kanti Sharma > > >