Hi Yzöwl, Sorry if I wasn't clear about this, I'm pretty new to this stuff. the blacklist.txt should contain IPs which will be excluded from the ping. for each line of the win-segment.txt file the script should verify if the IP is in the blacklist.txt file. if the IP does not exist it should ping it and write it in the alive.txt file. If the IP exists it should be skipped. Thanks, Nir