Postgresql: Unable to connect through psql at console to default localhost - postgresql

Postgresql server running and verified on 5432 on my localhost system:
If I type: psql -l I get the following response:
psql: could not connect to server: No such file or directory
Is the server running locally and accepting connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
If I type psql -h localhost -l, it works and gives me a list of the databases.
The pg_hba.conf file is wide open, showing:
TYPE DATABASE USER ADDRESS METHOD
The value "local" is for Unix domain socket connections only:
local all all trust
Allow any IP to connect without password:
host all all 0.0.0.0/0 trust
IPv4 local connections:
host all all 127.0.0.1/32 trust
IPv6 local connections:
host all all ::1/128 trust
What have I missed? On other systems the first call from the command line works fine.

It sounds like when you are running the command you are connecting to localhost, not the file socket.. try
psql -h localhost -p 5432

Default Admin Login sudo -u postgres psql
Login into specific db with privilages psql -h host -p port -U User_Name db_name

Is the server running locally and accepting connections on Unix domain
socket "/var/run/postgresql/.s.PGSQL.5432"?
This just means that the unix_socket_directory configuration parameter on the server differs from the default of the client-side psql.
/var/run/postgresql is the default Unix domain socket path for Debian-based packages. For a self-compiled server, it is /tmp. It may also be a custom path specified in postgresql.conf or through a start directive.
Assuming it's /tmp you could do psql -l -h /tmp. The command knows that the parameter following -h is to be interpreted as a directory and not as a hostname because it starts with a slash.

Related

extending IP range for postgres

Docker container, ubuntu20 it is.
I have manually installed postgres 12.9 in it.
when I do PGPASSWORD='mysecretpassword' psql -U postgres -p 5432 -h localhost (or 127.0.0.1) from inside a docker it works 100% OK - psql console appears
The problem appears when I try to replace localhost with non-loopback IP number. It either hangs or prints:
PGPASSWORD='mysecretpassword' psql -U postgres -p 5432 -h 172.17.0.5
psql: error: connection to server at "172.17.0.5", port 5432 failed: Connection refused
Is the server running on that host and accepting TCP/IP connections?
Also, what somehow is understandable, it prints same error when trying to access it from external machine (docker-host).
My /etc/postgresql/12/main/pg_hba.conf is:
local all postgres peer
local all all peer
host all all 127.0.0.1/32 md5
host all all ::1/128 md5
local replication all peer
host replication all 127.0.0.1/32 md5
host replication all ::1/128 md5
host all all 172.17.0.0/24 md5
host replication all 172.17.0.0/24 md5
with 2 lines at the end are added by me... unfortunately still it doesn't work.
Tried various other options 0.0.0.0/32 etc... can any1 explain me how to open my psql to all IPs ?

PostgreSQL local database access for user without password

I just create a user and new database on my local machine.
sudo su - postgres -c "createuser gauthier"
sudo su - postgres -c "createdb local-ag-db"
Then:
$ sudo -u postgres psql
sudo -u postgres psql
psql (11.9 (Debian 11.9-0+deb10u1))
Type "help" for help.
postgres=# grant all privileges on database "local-ag-db" to gauthier;
GRANT
I can access the database locally through a socket:
$ psql local-ag-db gauthier
psql (11.9 (Debian 11.9-0+deb10u1))
Type "help" for help.
local-ag-db=> \conninfo
You are connected to database "local-ag-db" as user "gauthier" via socket in "/var/run/postgresql" at port "5432".
But I cannot access it through localhost:
$ psql -d local-ag-db -h localhost -U gauthier
Password for user gauthier:
psql: fe_sendauth: no password supplied
My guess is that while createuser accepted to create a user without a password, logging in through the host requires identification that this user cannot provide.
This is the default content of /etc/postgresql/11/main/pg_hba.conf:
# Database administrative login by Unix domain socket
local all postgres peer
# TYPE DATABASE USER ADDRESS METHOD
# "local" is for Unix domain socket connections only
local all all peer
# IPv4 local connections:
host all all 127.0.0.1/32 md5
# IPv6 local connections:
host all all ::1/128 md5
# Allow replication connections from localhost, by a user with the
# replication privilege.
local replication all peer
host replication all 127.0.0.1/32 md5
host replication all ::1/128 md5
I have tried adding this at the end of that file, after reading the included documentation:
host local-ag-db gauthier samehost peer
but that did not work (after a restart sudo /etc/init.d/postgresql restart), it even broke my Unix socket access:
$ psql local-ag-db gauthier
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
I also tried this as last row of my config, with the same result:
host local-ag-db gauthier 127.0.0.1/32 peer
My questions:
how do I allow my local user to access the database through localhost?
how do I edit my conf file so that I don't break everything? (Unix socket method stops working when I add a rule)
On Debian.
You will need to add a line like:
host all all localhost trust
As you have no explicit rule currently it is dropping through to another catch all rule and prompting for authentication. Adrian's comment above is saying the same and likewise I don't suggest using trust outside of testing your connectivity - you really should assign a password and enforce it.
Adding entries to the pg_hba.conf needs care as the PostgreSQL will find the first match:
The first record with a matching connection type, client address, requested database, and user name is used to perform authentication. There is no “fall-through” or “backup”: if one record is chosen and the authentication fails, subsequent records are not considered. If no record matches, access is denied.
From https://www.postgresql.org/docs/current/auth-pg-hba-conf.html
Regarding
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
Looks like the restart may not have worked. Looks like no response rather than authentication failure.
Your server is not running. It never came back up when you tried to restart it, because you broke your hba. If you look in the log file, you should something like:
LOG: peer authentication is only supported on local sockets
FATAL: could not load pg_hba.conf
LOG: database system is shut down
Unbreak your pg_hba.conf and start the server again. Also, read your log files when you don't know what's going on. That is what they are there for.
You will need to choose a different method for authentication over localhost. ident is equivalent to peer, but it requires you to run the identd daemon on the server, and is not very secure for any addresses other than loopback ones.

Postgres -h connection works but without -h option gets Peer authentication failed for user

the below commands works
psql -h localhost -U <username> <dbname>
but
psql localhost -U <username> <dbname>
the above get psql: FATAL: Peer authentication failed for user
-h option lets you provide the hostname for your psql connection. If you remove -h option, then also remove localhost from your statement.
You can also check pg_hba.conf file for more debugging.
Because as #Lohit Gupta stated without -h psql ignores the hostname(localhost) and uses the default connection type. From docs:
https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-PARAMKEYWORDS
"
host
Name of host to connect to. If a host name begins with a slash, it specifies Unix-domain communication rather than TCP/IP communication; the value is the name of the directory in which the socket file is stored. The default behavior when host is not specified, or is empty, is to connect to a Unix-domain socket in /tmp (or whatever socket directory was specified when PostgreSQL was built). On machines without Unix-domain sockets, the default is to connect to localhost.
"
So in your case you have switched from connection type host to type local and a different set of connection rules will take over. As mentioned look in your pg_hba.conf file to see what those are. You should have also received the following error:
psql: warning: extra command-line argument "localhost" ignored

PostgreSql remote access on Ubuntu 10.04

I try do access remotely a Postgresql(10.3) db.
After I modify #listen_addresses = 'localhost' to listen_addresses = '*' or the ip, I get an error when I use:
sudo -u postgres psql
'Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
'
simply remove '#' - before - that means commented line.
UPDATE: if you changed postgresql's listen configuration, then default socket connection is not present. So if you specify exact IP for listen: listen_address = '192.168.1.2' then you need to connect via psql -h 192.168.1.2 -U postgres and your pg_hba.conf should contain entry similar to :
host all all 192.168.1.2/32 md5
and you will need to know postgres password. if you not worried about security - then simply use
host all all 192.168.1.2/32 trust
WARNING: do not use 'trust' configuration in production!

PostgreSQL: Remotely connecting to Postgres instance using psql command

I want to remotely connect to a Postgres instance. I know we can do this using the psql command passing the hostname
I tried the following:
psql -U postgres -p 5432 -h hostname
I modified the /etc/postgresql/9.3/main/pg_hba.conf file on the target machine to allow remote connections by default
I added the following line to the file
host all all source_ip/32 trust
I restarted the cluster using
pg_ctlcluster 9.2 mycluster stop
pg_ctlcluster 9.2 mycluster start
However, when I try to connect from the source_ip, I still get the error
Is the server running on host "" and accepting TCP/IP connections on port 5432?
What am I doing wrong here?
I resolved this issue using below options:
Whitelist your DB host from your network team to make sure you have access to remote host
Install postgreSQL version 4 or above
Run below command:
psql -h <REMOTE HOST> -p <REMOTE PORT> -U <DB_USER> <DB_NAME>
psql -h <IP_Address> -p <port_no> -d <database_name> -U <DB_username> -W
-W option will prompt for password. For example:
psql -h 192.168.1.50 -p 5432 -d testdb -U testuser -W
I figured it out.
Had to set listen_addresses='*' in postgresql.conf to allow for incoming connections from any ip / all ip
Step Wise below
Opening the Port - Make sure the PSQL Port is open to all remote connections or connections from a specific set of IPs as per your requirement. PSQL, in general, runs at port 5432, and it is configurable, so expose relevant Port accordingly.
Update Remote Server PSQL Configuration - Set listen_addresses = '*' in postgresql.conf file, path in general is /etc/postgresql/psql_version/main/postgresql.conf
Connect remotely - psql -U <db_username> -h <IP_address> - in case psql is running on a port other than 5432 on the remote server, specify port by adding -p <port_number>
A little plus below -
In case the IP has been mapped to a domain name, you can connect by replacing <IP_address> with <host_name>. To do this, add a new connection rule in pg_hba.conf file
Note -
All above explained can cause security issues - best practice always is to either keep your psql port closed, or only allow a list of IPs to connect through the port.
Note that "ident" in pg_hba.conf requires a "ident server" to be running on the client.