Remote connection getting closed - hitting an arbitary URL?

Your authentication should look something like this:

client.write(
"GET /camera_control.cgi?user=user&password=password&command=<command> HTTP/1.0\r\n"
"Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==\r\n"
"\r\n");

You can use this website to encode your USERNAME:PASSWORD in base64:

http://www.opinionatedgeek.com/dotnet/tools/base64encode/

For this example, "Aladdin:open sesame" has been encoded as "QWxhZGRpbjpvcGVuIHNlc2FtZQ==".