PostgreSQL Authentication Error: "FATAL: no pg_hba.conf entry for host"

Products

• VMware Tanzu Greenplum
• VMware Tanzu Data Suite
• VMware Tanzu Data Suite
• VMware Tanzu Greenplum / Gemfire

Issue/Introduction

When a PostgreSQL client receives the error message:

FATAL: no pg_hba.conf entry for host "xxx.xxx.xx.xx", user "xxx", database "xxx", SSL off

it indicates that PostgreSQL cannot find a matching authentication rule in pg_hba.conf for the connection attempt.

Common Causes

1. Missing Entry: No rule exists for the specific host/user/database combination

2. Rule Order Issues: Valid rule exists but appears after a more general rejection rule

3. Incorrect Network Information: IP address or subnet mask is incorrect

4. Configuration Not Reloaded: Changes to pg_hba.conf not applied with pg_reload_conf()

Hidden Cause: Invalid IP Address in Configuration

A critical but often overlooked cause is the presence of invalid IP addresses anywhere in pg_hba.conf. For example:

host all all 10.292.94.1/32 md5

Why this causes problems:

• IP octets must be between 0-255; "292" exceeds this limit

• PostgreSQL silently rejects the invalid entry and may invalidate the entire configuration

• New entries added to pg_hba.conf become ineffective, even at the beginning of the file

• gpstop -u or similar reload commands complete successfully with no error messages

• The system continues to use old authentication rules

Resolution

Resolution

1. Remove or correct any invalid IP addresses or subnet masks in pg_hba.conf

2. Ensure all entries use proper syntax and spacing

3. Reload PostgreSQL configuration:

    

   text

   SELECT pg_reload_conf();

   or

    

   text

   gpstop -u