AS20057 166.177.240.0/21 CIDR and IP Range Summary.ASN: 20057 - AT&T Mobility LLCHost Count: 2046Addressable IPs: 2048166.177.240.0/24166.177.241.0/24166.177.242.0/24166.177.243.0/24166.177.244.0/24166.177.245.0/24166.177.246.0/24166.177.247.0/24