The following bug has been logged online:

Bug reference: 2063
Logged by: neeraj chaudhari
Email address: neerajchaudhari@yahoo.co.in
PostgreSQL version: 8.0.4
Operating system: Red Hat linux 9.0
Description: Unsupported frontend protocol
Details:

Hi,
i have recently installed postgresql 8.0.4 on my red hat linux 9.0 box, i
have configured, make & installed successfully. The application server which
i use is jboss-3.2.6. Now whenever i start my database server (postgresql
8.0.4) and then my application server, i receive the following messages on
my database server:-


[ethuser@ethrl-edu32 pgsql]$ ./setenv
[ethuser@ethrl-edu32 pgsql]$ postmaster -D /usr/pgsql/data/
LOG: database system was shut down at 2005-11-22 11:39:34 IST
LOG: checkpoint record is at 0/D9CF8C
LOG: redo record is at 0/D9CF8C; undo record is at 0/0; shutdown TRUE
LOG: next transaction id: 30928; next oid: 19697
LOG: database system is ready
FATAL: unsupported frontend protocol
FATAL: unsupported frontend protocol
FATAL: unsupported frontend protocol
FATAL: unsupported frontend protocol
FATAL: unsupported frontend protocol

Then to i am able to connect to the database & access & modify the
records.

regards,
Neeraj

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""neeraj chaudhari"" <neerajchaudhari@yahoo.co.in> wrote
>
> FATAL: unsupported frontend protocol
> FATAL: unsupported frontend protocol
> FATAL: unsupported frontend protocol
>
> Then to i am able to connect to the database & access & modify the
> records.
>

It looks like your client guesses out the right frontend protocol version
after several tries, then stick to this version and continue.

But the strange thing is that you are using 8.0.4, why the fatal message is
not with this format:
"FATAL: unsupported frontend protocol %u.%u: server supports %u.0 to
%u.%u"

Regards,
Qingqing