Re: IPV6 issue

On Thu, Nov 23, 2023 at 2:18 PM Atul Kumar <akumar14871@gmail.com> wrote:

I have postgres 12 running in centos 7 on my two machines, recently I changed the authentication of entries of pg_hba.conf to scram-sha-256 for localhost.

Since then in my one machine, I have started getting the below error when I use command "psql postgres"

no pg_hba.conf entry for host "::1", user "postgres", database "postgres

I found that localhost is resolve to IPV6 by using below command:

getent hosts localhost

::1             localhost localhost.localdomain localhost6 localhost6.localdomain6

Then I tested the same issue in my second machine

getent hosts localhost

::1             localhost localhost.localdomain localhost6 localhost6.localdomain6

but in my second machine I didn't face any such issue while using command "psql postgres", I was able to login into the database without such error.

The pg_hba.conf on both machines are identical without having any IPV6 entry in it.

The entry of pg_hba.conf is like below:

# TYPE  DATABASE        USER            ADDRESS                 METHOD

 

# "local" is for Unix domain socket connections only

local   all           all                                          scram-sha-256

# IPv4 local connections:

host    all           postgres     127.0.0.1/32               scram-sha-256

I am not able to understand that my both machines are resolved to IPV6 then why is my first machine is throwing this error ?

That is curious.

Have you exported PGHOST on either server (in, for example, .pgsql_profile, .bash_profile or .bashrc)?  If it is set to localhost on the primary server then psql will complain like you noticed.  If it is unset on the secondary server, then psql will use the domain socket and not complain.