Repeating the Ping Scan W/O 113: nmap -sP -PS22,25,53,80,31338 -PA80,21000 -PU53,19000 -PE -PM -T4 -g 53 -oA foocorp-ps-no113 [netblocks] [...] [ Nmap run completed -- 4397 IP addresses (71 hosts up) scanned in 597.924 seconds ] 71 hosts is much easier to deal with than 950. Lets make a list of up hosts: > grep 'Status: Up' foocorp-ps-no113-040403.gnmap | cut "-d " -f2 > foocorp.ips.up [ Then I added the firewall we discovered -- fw.chi (216.163.143.130) ]