Issues in rewriting client side

First, query name by getaddrinfo()
Do not socket() before name resolution; AF can change.

Loop through the names returned
The DNS database for the peer may wrongly be configured.
IPv4 network can be down while IPv6 is alive, and vice versa.

Use a port number/name string, not htons(port)

IPv4 mapped address (e.g. ::ffff:127.0.0.1)
Using IPv4 transport from AF_INET6 socket.
Do not rely on this - complicated specification, low portability.