AS3257 216.221.144.0/21 CIDR and IP Range Summary.ASN: 3257 - GTT Communications Inc.Host Count: 2046Addressable IPs: 2048216.221.144.0/24216.221.145.0/24216.221.146.0/24216.221.147.0/24216.221.148.0/24216.221.149.0/24216.221.150.0/24216.221.151.0/24