Thread: Problem with postgresql database connection in combination with HUAWEI data modem

Hello,

I discussed my problem at www.pg-forum.de with Mr. Scherbaum (ADS)  and he recommended me to inform you about this
problem.

I worked on my Mac-Book (Mac OS X 10.6.6) with postgresql database version 9 (postgresql-9.0.1-1-osx.dmg). After
installingand connecting my HUAWEI E122 data modem (net provider 3 (drei)), I have detected, that I could't connect to
database.  
Disconnecting the HUAWEI modem has no effects. I could not connect to database. Restarting the system makes the
databaseavailable again. 
The problem occurs exactly at connecting to internet from 3DataManager. There are no problems with connecting USB-Stick
toMac Book or starting the 3DataManager.  

I installed the postgresql-database with default settings:

host: localhost
port: 5432
user: postgres

listen_addresses: *

This is a netstat-result after connecting via HUAWEI data modem:

Active Internet connections (including servers)
Proto Recv-Q Send-Q Local Address Foreign Address (state)
tcp4 0 0 178.113.226.250..52044 c-98-245-185-91..56489 ESTABLISHED
tcp4 0 0 *.21234 *.* LISTEN
tcp4 0 0 *.postgresql *.* LISTEN
tcp6 0 0 *.postgres *.* LISTEN
tcp4 0 0 .psf.ipp *.* LISTEN
tcp6 0 0 localhost.ipp *.* LISTEN

Trying to start a telnet-connection, the result was:

telnet 127.0.0.1 5432
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Operation timed out
telnet: Unable to connect to remote host

As I had no idea, what the problem could be, I tried installing the latest version of postgresql
(postgresql-9.0.2-1-osx.dmg),maybe that this problem is fixed now.  
But it has no effect.

Then I tried reproducing the problem on my Windows 7 system. I installed the HUAWEI data stick and connected it to the
internet. 

I could connect to database without problems!! So I checked the version of postgresql on my windows system. The version
is8.4! (postgresql-8.4.2-1-windows.exe) 

After uninstalling of postgresql 9 from my Mac Book and installing the latest 8.4 version (postgresql-8.4.6-1-osx.dmg),
theproblem was also solved. 

Maybe that the problem is a 32/64 bit problem.

best regards,

Juergen Wolfsgruber

2011/1/31 Jürgen Wolfsgruber <juergen.wolfsgruber@gmail.com>:
> Trying to start a telnet-connection, the result was:
>
> telnet 127.0.0.1 5432
> Trying 127.0.0.1...
> telnet: connect to address 127.0.0.1: Operation timed out
> telnet: Unable to connect to remote host

That's just bizarre.  How can you get a network timeout over the
loopback address?

Your data modem is probably doing something funky to your network
stack, but I don't know what.  Can you connect to PostgreSQL over a
UNIX socket when the system is in this state?  Does stuff continue to
show up in the log file?  (e.g. If you send the postmaster a SIGTERM
while it's like this, do you see shutdown messages?)

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

On 02/03/2011 04:45 PM, Robert Haas wrote:
> Your data modem is probably doing something funky to your network
> stack, but I don't know what.

Are other network services affected as well?  In that case, I'd file a
bug against the modem driver software.

Regards

Markus Wanner