Question

I am writing a server application that will provide a service on an ephemeral port that I only want accessible on the loopback interface. In order to do this, I am writing code like the following:

struct sockaddr_in bind_addr;

memset(&bind_addr,0,sizeof(bind_addr));
bind_addr.sin_family = AF_INET;
bind_addr.sin_port = 0;
bind_addr.sin_addr.s_addr = htonl(inet_addr("127.0.0.1"));
rcd = ::bind(
   socket_handle,
   reinterpret_cast<struct sockaddr *>(&bind_addr),
   sizeof(bind_addr));

The return value for this call to bind() is -1 and the value of errno is 99 (Cannot assign requested address). Is this failing because inet_addr() already returns its result in network order or is there some other reason?

Answer 1

Is this failing because inet_addr() already returns its result in network order

Yes.

So remove the htonl call.