Curl localhost from within vagrant VM results in 'Empty reply from server'

Question

I started a deepstream server in a vagrant vm. The server says it's

Listening for websocket connections on 0.0.0.0:6020/deepstream

The /etc/hosts in the vm:

# 0.0.0.0   localhost
127.0.0.1 localhost
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

When I curl the deepstream server from within the vm, I get

curl 'http://0.0.0.0:6020/deepstream'
curl: (52) Empty reply from server

I tried starting the server with localhost, 127.0.0.1, and 0.0.0.0. I also tried curling these three addresses to no avail.

Answer 1

Listening on 0.0.0.0 means listening on all local IP addresses.

Try curl http://127.0.0.1:6020/deepstream to access it from the VM itself. Or use any other IP address on your VM - a non-localhost IP address is required if you want to access it from another machine (including the VM's host). Or any hostname that resolves to any of the IP addresses on your VM.

If your VM doesn't have any other IP addresses then that's a problem you need to solve if you want to access any network services on it from outside the VM. That's beyond the scope of this question, post a new question with details of your VM's setup (including vagrant config, and local dhcp server if any)

Note: It is a good idea to monitor the deepstream server's log file in another terminal, e.g. by running tail -f and then trying to connect, at least while you are debugging the initial setup (or any other time when there are problems).

BTW, you should get rid of the 0.0.0.0 entry in /etc/hosts and uncomment the 127.0.0.1 entry. 0.0.0.0 is NOT localhost and it is not a synonym for localhost.