Host Verification while SSHing

The first time you SSH to a remote host, you need to verify the fingerprint of the host.
```
The authenticity of host 'example.com (1.1.1.1)' can't be established.
ECDSA key fingerprint is SHA256:suhfbwrunauibgsrbgeuygbsltnhubsiff.
Are you sure you want to continue connecting (yes/no)?
```
MITM prevention
------
For MITM prevention, here's how:
1. Local machine cmd:
```bash
ssh -o FingerprintHash=md5 example.com
```

1. Remote host cmd: 
Find a secure way to execute the below codes on your remote host and output host ssh fingerprint.
    * Web console via https. Or
    * Goto physical place of remote host. Or
    * Ask your VPS hoster for the fingerprint.
```bash
ssh-keygen -l -E md5 -f /etc/ssh/ssh_host_ecdsa_key.pub

# ssh-keygen -l            -f /etc/ssh/ssh_host_ecdsa_key.pub # if -E option not supported.
```

1. Compare the two fingerprints.