Access to remote pipes in Vista

I continue experimenting with Named Pipes. I had Pipe Server installed at Windows XP and client running under Windows Vista. Everything worked fined. But then I changed it and run Server on Vista and client on XP. Suddenly I got message "Logon failure: unknown user name or bad password."

Apparently, I didn't enable file sharing on Vista computer. So, to use pipes remotely you have to enable file sharing.