Re: Postgres 9.4 + unixODBC on Centos 6.5 problem connecting localhost postgres instance with isql ODBC commandline client - Mailing list pgsql-odbc

Hi Jeremy

> You probably want to set ServerName back to localhost in your odbc.ini
file, I had you change it to /tmp when I thought psql was using a unix
domain socket.

Ok, I set it back to localhost, and tried again, same result - IPV6 is used,
and the database name is randomly corrupted in the raw packet data if one
tries to connect via isql.

> It is strange that tcpdump is picking up this connection, if the postgres
driver is using the ServerName parameter then there should NOT have been a
TCP connection.

Hmm - ok my tcpdump command was literally just to dump anything sent to /
from the 5432 postgres port on 127.0.0.1 / localhost - and for each failed
isql connection attempt over IPV6 exactly 13 packets are collected, and the
database name is always corrupt (if I'm reading it right!)

>Have you tried doing the tcpdump on a psql connection attempt for
comparison?

Yes, psql  emits more packets (28 for a login and logout), runs on IPV4,
works correctly, and the database name is always correctly specified and not
corrupted. Postgress accepts the connection.

I find it interesting that the isql connection attempt fails with almost
half the number of packets as the psql connection attempt (depending on ODBC
protocol overhead?) indicating that isql fails about 1/2 way through the
required amount of packets to send to establish a Postgres connection?

I've got a feeling if I can somehow force isql to use IPV4 to postgress that
will already be a big step in the right direction... but how does one do
that?

Thanks

Regards

Stefan

-----Original Message-----
From: Faith, Jeremy [mailto:jfaith@tycoint.com]
Sent: Tuesday,July 21, 2015 11:08 AM
To: Stefan Viljoen; pgsql-odbc@postgresql.org
Subject: RE: [ODBC] Postgres 9.4 + unixODBC on Centos 6.5 problem connecting
localhost postgres instance with isql ODBC commandline client

Hi Stefan,

You probably want to set ServerName back to localhost in your odbc.ini file,
I had you change it to /tmp when I thought psql was using a unix domain
socket.

It is strange that tcpdump is picking up this connection, if the postgres
driver is using the ServerName parameter then there should NOT have been a
TCP connection.

Have you tried doing the tcpdump on a psql connection attempt for
comparison?

Regards,
Jeremy Faith
________________________________________
From: pgsql-odbc-owner@postgresql.org [pgsql-odbc-owner@postgresql.org] on
behalf of Stefan Viljoen [viljoens@verishare.co.za]
Sent: 21 July 2015 09:25
To: pgsql-odbc@postgresql.org
Subject: Re: [ODBC] Postgres 9.4 + unixODBC on Centos 6.5 problem connecting
localhost postgres instance with isql ODBC commandline client

Hi List

The plot thickens - I have now resorted to doing a tcpdump of the postgres
port and then trying to connect via isql.

The tcpdump command used was

---
tcpdump -vvvvv -x -X -s 65535 -i lo 'port 5432' -w post.pcap
---

This has revealed that in the post.pcap file (even just viewing the raw
packet data with vi in the terminal) that the REASON postgress keeps
rejecting isql login attempts is that isql apparently passes the database
name only partially, or corrupts it randomly...

E. g. I tried this five or six times and each time, the packets sent from
unixODBC / isql binary, specifies the string

asteriskcdrdb

which denotes the database name to postgress (and therefore is critical to
control login) as

&%%@%!db
*&#!@#drdb
!@&&%$idb

etc. and sometimes mixed / along with some other ASCII crud I cannot
duplicate here.

SSL is most definitely off so this cannot be encryption?

The STRANGE thing is I can spot the username (asteriskcdruser) in the packet
data and that is ALWAYS correct and uncorrupted, and is always passed as
"asteriskcdruser".

But the database name is -always- corrupted that is sent to port 5432 from
isql to login to postgress.

So if I do with isql

---
isql -v pgdb-cdr asteriskcdruser pword
---

In effect I try to login to postgress with

*&#!@#drdb

(as indicated by the packet data)  which is of course a database that does
not exist, nor is there a role that matches "asteriskcdruser" for such a
database.

From there the error

[S1000][unixODBC]The database does not exist on the server or user
authentication failed.
[ISQL]ERROR: Could not SQLConnect

which is completely logical as I'm trying to log into non-existent databases
as passed over ODBC from isql, no?

Any thoughts? How can this be fixed?

ODBC connections on the same box over the lo interface to MySQL keep working
100% - wonder why unixODBC is corrupting the database name, but ONLY when
passing it to Psql-odbc?

Or am I completely barking up the wrong tree?

Thanks

Stefan



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