Using Paralles port forwarding, could access by 127.0.0.1 but not localhost

Question

I'm using Paralles, and I make my local port 80 on my Mac(The host machine) forward to the port 80 of the ubuntu (The Paralles VM).

Then on my host machine, I check the port by netstat, and get

tcp4       0      0  *.http                 *.*                    LISTEN

The problem is that I can't access the service by http://localhost/, but I can access the service by http://127.0.0.1/.

Why the localhost not work while the 127.0.0.1 works?

When I try nmap -p 80 localhost, the result is:

Nmap scan report for localhost (127.0.0.1)
Host is up (0.00012s latency).
PORT   STATE SERVICE
80/tcp open  http