I have 3 instances now.

1. Airbyte server (A)

2. Postgre Database (B)

3. PC (C) – for testing

My purpose is to build a connection from A to B.

Firstly, I used Airbyte UI to create a destination for Postgre Database.

Then, it shows connection failed.

Therefore, I ssh to their instance to figure out what happens.

1. Modified the file pg_hba.conf in B

# Allow replication connections from localhost, by a user with the
# replication privilege.
local   replication     all                                     peer
host    replication     all             127.0.0.1/32            scram-sha-256
host    replication     all             ::1/128                 scram-sha-256
host    all             all             <private-ip-A>/32         md5
host    all             all             <public-ip-A>/32          md5
host    all             all             <public-ip-C>/32          md5

2. Modified the file postgresql.conf in B

# - Connection Settings -

listen_addresses = '*'                  # what IP address(es) to listen on;

3. After these two settings, C (for testing) can instantly be logged into the Postgre Database with a specific user.

4. Therefore, I start testing their internet using Telnet/ping function.

Telnet – For A to B:

    telnet <public-ip-B> 5432
    Trying <public-ip-B>... (then nothing)

Telnet – For C to B:

    telnet <public-ip-B> 5432
    Trying <public-ip-B>... 
    Connected to <public-ip-B>.

Ping – For A to B&C:

ping <public-ip-B> 
11 packets transmitted, 0 received, 100% packet loss, time 10250ms

ping <public-ip-C>
64 bytes from <public-ip-C>: icmp_seq=1 ttl=49 time=36.4 ms
64 bytes from <public-ip-C>: icmp_seq=2 ttl=49 time=37.9 ms
3 packets transmitted, 3 received, 0% packet loss, time 2002ms

Ping – For B to A&C: it is similar to A. Connected with C but not connected with B.

Ping -For C to A&B:

ping <public-ip-A>
3 packets transmitted, 0 received, 100% packet loss, time 2105ms

ping <public-ip-B>
6 packets transmitted, 0 received, 100% packet loss, time 5201ms

Then, I don’t have any ideas now what I should try next for help me made connection from A to B.