str = "21:51:05.908379 IP 69.70.85.212.bahnhof.se.ntp > 39.108.66.17.46303: NTPv2, Reserved, length 440
21:51:05.908423 IP 46.101.254.124.ntp > 39.108.66.17.50901: NTPv2, Reserved, length 440
21:51:05.908423 IP 46.101.254.124.ntp > 39.108.66.17.50901: NTPv2, Reserved, length 440
21:51:05.908425 IP 46.101.254.124.ntp > 39.108.66.17.50901: NTPv2, Reserved, length 440
21:51:05.908436 IP 46.101.254.124.ntp > 39.108.66.17.50901: NTPv2, Reserved, length 440
21:51:05.908438 IP 46.101.254.124.ntp > 39.108.66.17.50901: NTPv2, Reserved, length 440
";

regex=/^[^I]*IP ([^>]*)>.*$/;

arr = [];

str.scan(regex).each{|m|arr.push m }

arr = arr.uniq

puts arr
puts arr.length