El archivo /etc/hosts
en mi MacBook Pro que ejecuta macOS High Sierra 10.13.6 tiene las siguientes líneas adicionales en la parte superior de mi archivo de hosts. Si los quito vuelven.
216.239.32.20 www.google.ac # __CE_WATERMARK__
216.239.32.20 www.google.ad # __CE_WATERMARK__
216.239.32.20 www.google.ae # __CE_WATERMARK__
216.239.32.20 www.google.al # __CE_WATERMARK__
216.239.32.20 www.google.am # __CE_WATERMARK__
216.239.32.20 www.google.as # __CE_WATERMARK__
216.239.32.20 www.google.at # __CE_WATERMARK__
216.239.32.20 www.google.az # __CE_WATERMARK__
216.239.32.20 www.google.ba # __CE_WATERMARK__
216.239.32.20 www.google.be # __CE_WATERMARK__
216.239.32.20 www.google.bf # __CE_WATERMARK__
216.239.32.20 www.google.bg # __CE_WATERMARK__
216.239.32.20 www.google.bi # __CE_WATERMARK__
216.239.32.20 www.google.bj # __CE_WATERMARK__
216.239.32.20 www.google.bs # __CE_WATERMARK__
216.239.32.20 www.google.bt # __CE_WATERMARK__
216.239.32.20 www.google.by # __CE_WATERMARK__
216.239.32.20 www.google.ca # __CE_WATERMARK__
216.239.32.20 www.google.cat # __CE_WATERMARK__
216.239.32.20 www.google.cc # __CE_WATERMARK__
216.239.32.20 www.google.cd # __CE_WATERMARK__
216.239.32.20 www.google.cf # __CE_WATERMARK__
216.239.32.20 www.google.cg # __CE_WATERMARK__
216.239.32.20 www.google.ch # __CE_WATERMARK__
216.239.32.20 www.google.ci # __CE_WATERMARK__
216.239.32.20 www.google.cl # __CE_WATERMARK__
216.239.32.20 www.google.cm # __CE_WATERMARK__
216.239.32.20 www.google.cn # __CE_WATERMARK__
216.239.32.20 www.google.co.ao # __CE_WATERMARK__
216.239.32.20 www.google.co.bw # __CE_WATERMARK__
216.239.32.20 www.google.co.ck # __CE_WATERMARK__
216.239.32.20 www.google.co.cr # __CE_WATERMARK__
216.239.32.20 www.google.co.id # __CE_WATERMARK__
216.239.32.20 www.google.co.il # __CE_WATERMARK__
216.239.32.20 www.google.co.in # __CE_WATERMARK__
216.239.32.20 www.google.co.jp # __CE_WATERMARK__
216.239.32.20 www.google.co.ke # __CE_WATERMARK__
216.239.32.20 www.google.co.kr # __CE_WATERMARK__
216.239.32.20 www.google.co.ls # __CE_WATERMARK__
216.239.32.20 www.google.co.ma # __CE_WATERMARK__
216.239.32.20 www.google.co.mz # __CE_WATERMARK__
216.239.32.20 www.google.co.nz # __CE_WATERMARK__
216.239.32.20 www.google.co.th # __CE_WATERMARK__
216.239.32.20 www.google.co.tz # __CE_WATERMARK__
216.239.32.20 www.google.co.ug # __CE_WATERMARK__
216.239.32.20 www.google.co.uk # __CE_WATERMARK__
216.239.32.20 www.google.co.uz # __CE_WATERMARK__
216.239.32.20 www.google.co.ve # __CE_WATERMARK__
216.239.32.20 www.google.co.vi # __CE_WATERMARK__
216.239.32.20 www.google.co.za # __CE_WATERMARK__
216.239.32.20 www.google.co.zm # __CE_WATERMARK__
216.239.32.20 www.google.co.zw # __CE_WATERMARK__
216.239.32.20 www.google.com # __CE_WATERMARK__
216.239.32.20 www.google.com.af # __CE_WATERMARK__
216.239.32.20 www.google.com.ag # __CE_WATERMARK__
216.239.32.20 www.google.com.ai # __CE_WATERMARK__
216.239.32.20 www.google.com.ar # __CE_WATERMARK__
216.239.32.20 www.google.com.au # __CE_WATERMARK__
216.239.32.20 www.google.com.bd # __CE_WATERMARK__
216.239.32.20 www.google.com.bh # __CE_WATERMARK__
216.239.32.20 www.google.com.bn # __CE_WATERMARK__
216.239.32.20 www.google.com.bo # __CE_WATERMARK__
216.239.32.20 www.google.com.br # __CE_WATERMARK__
216.239.32.20 www.google.com.bz # __CE_WATERMARK__
216.239.32.20 www.google.com.co # __CE_WATERMARK__
216.239.32.20 www.google.com.cu # __CE_WATERMARK__
216.239.32.20 www.google.com.cy # __CE_WATERMARK__
216.239.32.20 www.google.com.do # __CE_WATERMARK__
216.239.32.20 www.google.com.ec # __CE_WATERMARK__
216.239.32.20 www.google.com.eg # __CE_WATERMARK__
216.239.32.20 www.google.com.et # __CE_WATERMARK__
216.239.32.20 www.google.com.fj # __CE_WATERMARK__
216.239.32.20 www.google.com.gh # __CE_WATERMARK__
216.239.32.20 www.google.com.gi # __CE_WATERMARK__
216.239.32.20 www.google.com.gt # __CE_WATERMARK__
216.239.32.20 www.google.com.hk # __CE_WATERMARK__
216.239.32.20 www.google.com.jm # __CE_WATERMARK__
216.239.32.20 www.google.com.kh # __CE_WATERMARK__
216.239.32.20 www.google.com.kw # __CE_WATERMARK__
216.239.32.20 www.google.com.lb # __CE_WATERMARK__
216.239.32.20 www.google.com.lc # __CE_WATERMARK__
216.239.32.20 www.google.com.ly # __CE_WATERMARK__
216.239.32.20 www.google.com.mm # __CE_WATERMARK__
216.239.32.20 www.google.com.mt # __CE_WATERMARK__
216.239.32.20 www.google.com.mx # __CE_WATERMARK__
216.239.32.20 www.google.com.my # __CE_WATERMARK__
216.239.32.20 www.google.com.na # __CE_WATERMARK__
216.239.32.20 www.google.com.nf # __CE_WATERMARK__
216.239.32.20 www.google.com.ng # __CE_WATERMARK__
216.239.32.20 www.google.com.ni # __CE_WATERMARK__
216.239.32.20 www.google.com.np # __CE_WATERMARK__
216.239.32.20 www.google.com.om # __CE_WATERMARK__
216.239.32.20 www.google.com.pa # __CE_WATERMARK__
216.239.32.20 www.google.com.pe # __CE_WATERMARK__
216.239.32.20 www.google.com.pg # __CE_WATERMARK__
216.239.32.20 www.google.com.ph # __CE_WATERMARK__
216.239.32.20 www.google.com.pk # __CE_WATERMARK__
216.239.32.20 www.google.com.pr # __CE_WATERMARK__
216.239.32.20 www.google.com.py # __CE_WATERMARK__
216.239.32.20 www.google.com.qa # __CE_WATERMARK__
216.239.32.20 www.google.com.sa # __CE_WATERMARK__
216.239.32.20 www.google.com.sb # __CE_WATERMARK__
216.239.32.20 www.google.com.sg # __CE_WATERMARK__
216.239.32.20 www.google.com.sl # __CE_WATERMARK__
216.239.32.20 www.google.com.sv # __CE_WATERMARK__
216.239.32.20 www.google.com.tj # __CE_WATERMARK__
216.239.32.20 www.google.com.tn # __CE_WATERMARK__
216.239.32.20 www.google.com.tr # __CE_WATERMARK__
216.239.32.20 www.google.com.tw # __CE_WATERMARK__
216.239.32.20 www.google.com.ua # __CE_WATERMARK__
216.239.32.20 www.google.com.uy # __CE_WATERMARK__
216.239.32.20 www.google.com.vc # __CE_WATERMARK__
216.239.32.20 www.google.com.vn # __CE_WATERMARK__
216.239.32.20 www.google.cv # __CE_WATERMARK__
216.239.32.20 www.google.cz # __CE_WATERMARK__
216.239.32.20 www.google.de # __CE_WATERMARK__
216.239.32.20 www.google.dj # __CE_WATERMARK__
216.239.32.20 www.google.dk # __CE_WATERMARK__
216.239.32.20 www.google.dm # __CE_WATERMARK__
216.239.32.20 www.google.dz # __CE_WATERMARK__
216.239.32.20 www.google.ee # __CE_WATERMARK__
216.239.32.20 www.google.es # __CE_WATERMARK__
216.239.32.20 www.google.fi # __CE_WATERMARK__
216.239.32.20 www.google.fm # __CE_WATERMARK__
216.239.32.20 www.google.fr # __CE_WATERMARK__
216.239.32.20 www.google.ga # __CE_WATERMARK__
216.239.32.20 www.google.ge # __CE_WATERMARK__
216.239.32.20 www.google.gf # __CE_WATERMARK__
216.239.32.20 www.google.gg # __CE_WATERMARK__
216.239.32.20 www.google.gl # __CE_WATERMARK__
216.239.32.20 www.google.gm # __CE_WATERMARK__
216.239.32.20 www.google.gp # __CE_WATERMARK__
216.239.32.20 www.google.gr # __CE_WATERMARK__
216.239.32.20 www.google.gy # __CE_WATERMARK__
216.239.32.20 www.google.hn # __CE_WATERMARK__
216.239.32.20 www.google.hr # __CE_WATERMARK__
216.239.32.20 www.google.ht # __CE_WATERMARK__
216.239.32.20 www.google.hu # __CE_WATERMARK__
216.239.32.20 www.google.ie # __CE_WATERMARK__
216.239.32.20 www.google.im # __CE_WATERMARK__
216.239.32.20 www.google.io # __CE_WATERMARK__
216.239.32.20 www.google.iq # __CE_WATERMARK__
216.239.32.20 www.google.ir # __CE_WATERMARK__
216.239.32.20 www.google.is # __CE_WATERMARK__
216.239.32.20 www.google.it # __CE_WATERMARK__
216.239.32.20 www.google.je # __CE_WATERMARK__
216.239.32.20 www.google.jo # __CE_WATERMARK__
216.239.32.20 www.google.kg # __CE_WATERMARK__
216.239.32.20 www.google.ki # __CE_WATERMARK__
216.239.32.20 www.google.kz # __CE_WATERMARK__
216.239.32.20 www.google.la # __CE_WATERMARK__
216.239.32.20 www.google.li # __CE_WATERMARK__
216.239.32.20 www.google.lk # __CE_WATERMARK__
216.239.32.20 www.google.lt # __CE_WATERMARK__
216.239.32.20 www.google.lu # __CE_WATERMARK__
216.239.32.20 www.google.lv # __CE_WATERMARK__
216.239.32.20 www.google.md # __CE_WATERMARK__
216.239.32.20 www.google.me # __CE_WATERMARK__
216.239.32.20 www.google.mg # __CE_WATERMARK__
216.239.32.20 www.google.mk # __CE_WATERMARK__
216.239.32.20 www.google.ml # __CE_WATERMARK__
216.239.32.20 www.google.mn # __CE_WATERMARK__
216.239.32.20 www.google.ms # __CE_WATERMARK__
216.239.32.20 www.google.mu # __CE_WATERMARK__
216.239.32.20 www.google.mv # __CE_WATERMARK__
216.239.32.20 www.google.mw # __CE_WATERMARK__
216.239.32.20 www.google.ne # __CE_WATERMARK__
216.239.32.20 www.google.nl # __CE_WATERMARK__
216.239.32.20 www.google.no # __CE_WATERMARK__
216.239.32.20 www.google.nr # __CE_WATERMARK__
216.239.32.20 www.google.nu # __CE_WATERMARK__
216.239.32.20 www.google.pl # __CE_WATERMARK__
216.239.32.20 www.google.pn # __CE_WATERMARK__
216.239.32.20 www.google.ps # __CE_WATERMARK__
216.239.32.20 www.google.pt # __CE_WATERMARK__
216.239.32.20 www.google.ro # __CE_WATERMARK__
216.239.32.20 www.google.rs # __CE_WATERMARK__
216.239.32.20 www.google.ru # __CE_WATERMARK__
216.239.32.20 www.google.rw # __CE_WATERMARK__
216.239.32.20 www.google.sc # __CE_WATERMARK__
216.239.32.20 www.google.se # __CE_WATERMARK__
216.239.32.20 www.google.sh # __CE_WATERMARK__
216.239.32.20 www.google.si # __CE_WATERMARK__
216.239.32.20 www.google.sk # __CE_WATERMARK__
216.239.32.20 www.google.sm # __CE_WATERMARK__
216.239.32.20 www.google.sn # __CE_WATERMARK__
216.239.32.20 www.google.so # __CE_WATERMARK__
216.239.32.20 www.google.st # __CE_WATERMARK__
216.239.32.20 www.google.td # __CE_WATERMARK__
216.239.32.20 www.google.tg # __CE_WATERMARK__
216.239.32.20 www.google.tk # __CE_WATERMARK__
216.239.32.20 www.google.tl # __CE_WATERMARK__
216.239.32.20 www.google.tm # __CE_WATERMARK__
216.239.32.20 www.google.tn # __CE_WATERMARK__
216.239.32.20 www.google.to # __CE_WATERMARK__
216.239.32.20 www.google.tt # __CE_WATERMARK__
216.239.32.20 www.google.us # __CE_WATERMARK__
216.239.32.20 www.google.vg # __CE_WATERMARK__
216.239.32.20 www.google.vu # __CE_WATERMARK__
216.239.32.20 www.google.ws # __CE_WATERMARK__
¿Qué está causando que aparezcan las líneas y cómo puedo evitar que esto suceda?