31.221.128.0/19 covers 31.221.128.0 to 31.221.159.255, 8,192 IPv4 addresses. It is announced by AS15704 (Xtra Telecom S.A.). Every sampled address geolocates to Spain, with 75% in Bilbao. It is registered to an internet service provider. 19% of sampled addresses are flagged as proxy.