PgAdmin III - How to connect to database when password is empty?

Question

I have installed PostgreSQL 9.1 on my PC (Win 7). I have a small Java application connecting successfully to it with login=sa and password="". The connection works.

However, it is refused from PgAdmin III itself. I get:

Error connecting to the server: fe_sendauth: no password supplied

How do I connect to my database from PgAdmin III with an empty password?

EDIT

This is just a test, not production code.

• Peter Eisentraut: I don't know for sure, but it's easy to imagine that PgAdmin doesn't support that.
• Jack Douglas: is your Java app on the same client as pgAdmin?
• Jack Douglas: similar question

Answer 1

I can connect to my postgres instance from pgAdmin III without a password for any user including superusers such as postgres.

Because you are connecting ok from another client, there is no reason you should not be able to connect from pgAdmin if they are on the same workstation - unless some firewall rule on the client itself is allowing one program but not another.

If the problem is specific to this client, you may need to change one or more of:

• pg_hba.conf

host sa all 192.168.0.nnn/32 trust

• postgresql.conf

listen_addresses = '*'

• the firewall on your postgres server, eg iptables:

-A INPUT -s 192.168.0.nnn -m state --state NEW -j ACCEPT

But I recommend you don't do any of this. The manual says the following with good reason:

trust authentication is only suitable for TCP/IP connections if you trust every user on every machine that is allowed to connect to the server by the pg_hba.conf lines that specify trust. It is seldom reasonable to use trust for any TCP/IP connections other than those from localhost (127.0.0.1).

Instead, consider either:

• using a password and md5 identification
• tunnelling port 5432 over ssh

Answer 2

I found this answer elsewhere.

If your DB is on the local host, try leaving the host field blank in the connection as opposed to using "localhost" or "127.0.0.1′′. This tells PgAdmin to connect via the local unix socket instead of TCP.

• András Váczi: Let's add that the original question was about a Windows system.
• basicdays: Ah this was exactly it. Leaving host blank worked.
• Athlan: You cannot leave this field blank, it is required.
• a1an: It looks like leaving the host field blank works only if you have a role in pg named as your system username (on Linux). Otherwise I guess user maps are needed.
• user113443: Perfect! With a fresh install of postgresql and pgadmin, changing pg_hba.conf to say trust instead of peer in this line - local all postgres trust, and leaving the host and password fields blank in pgadmin gets everything working! I wish pgadmin would add a checkbox to switch to sockets instead of this hard to discover UI.