Phabricator/Ban IP address

Block IP in Varnish

You are probably searching for edge blocking an IP: Varnish#Blocklist_an_IP.

Look for phabricator_abusers: in file /srv/private/hieradata/common.yaml

Block IP in SUL

Most Phabricator spammers create a SUL account, then use that to log in to Phab. So global IP banning them on metawiki should lock them out from creating new accounts. Contact your favorite steward to arrange this.