As long as you manually get the IP for every domain. I.e. if they ask for "blah.com" you have to get the IP, check it, then turn it into "curl -H 'Host: blah.co

As long as you manually get the IP for every domain. I.e. if they ask for "blah.com" you have to get the IP, check it, then turn it into "curl -H 'Host: blah.com' http://IP" http://IP". (Otherwise, it may be a race condition that allows the DNS server to resolve to a different IP address the 2nd time. See https://en.wikipedia.org/wiki/Time_of_check_to_time_of_use https://en.wikipedia.org/wiki/Time_of_check_to_time_of_use )