The nslookup function is similar to nsl but works on all platforms
and can resolve ipv6 addresses if supported by the OS. Default behavior raises an
error if lookup fails. The has_internet function tests the internet
connection by resolving a random address.
# NOT RUN {# Should always work if we are onlinenslookup("www.r-project.org")
# If your OS supports IPv6nslookup("ipv6.test-ipv6.com", ipv4_only = FALSE, error = FALSE)
# }