2026-08-25 05:21 @216.73.216.179
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DBI::ProxyServer - a server for the DBD::Proxy driver
| Use Case | Command | Description |
|---|---|---|
| Start server with config | dbiproxy --configfile proxy.cfg | Launch proxy daemon using a configuration file |
| Run in debug mode | dbiproxy --debug | Enable verbose debug logging |
| Connect via DBD::Proxy | DBI->connect("dbi:Proxy:hostname=host;port=12400;dsn=dbi:Oracle:e01", $user, $pass) | Client connects through the proxy to a remote database |
| Restrict by IP and user | { mask => '^10\.', accept => 1, users => [ 'bob' ] } | Allow/deny based on client IP and username list |
| Restrict SQL queries | sql => { alias => 'SELECT ... WHERE col = ?' } | Only named query aliases can be executed |
| Use query alias with bind | $dbh->prepare("alias"); $cur->bind_param(1, $val); | Execute a predefined query using parameter binding |
use DBI::ProxyServer;
DBI::ProxyServer::main(@ARGV);
DBD::Proxy Server is a module for implementing a proxy for the DBI proxy driver, DBD::Proxy. It allows access to databases over the network if the DBMS does not offer networked operations. But the proxy server might be useful for you, even if you have a DBMS with integrated network functionality: It can be used as a DBI proxy in a firewalled environment.
DBI::ProxyServer runs as a daemon on the machine with the DBMS or on the firewall. The client connects to the agent using the DBI driver DBD::Proxy, thus in the exactly same way than using DBD::mysql, DBD::mSQL or any other DBI driver.
The agent is implemented as a RPC::PlServer application. Thus you have access to all the possibilities of this module, in particular encryption and a similar configuration file. DBI::ProxyServer adds the possibility of query restrictions: You can define a set of queries that a client may execute and restrict access to those. (Requires a DBI driver that supports parameter binding.) See "CONFIGURATION FILE".
The provided driver script, dbiproxy, may either be used as it is or used as the basis for a local version modified to meet your needs.
When calling the DBI::ProxyServer::main() function, you supply an array of options. These options are parsed by the Getopt::Long module. The ProxyServer inherits all of RPC::PlServer's and hence Net::Daemon's options and option handling, in particular the ability to read options from either the command line or a config file. See RPC::PlServer. See Net::Daemon. Available options include
chroot (--chroot=dir)
(UNIX only) After doing a bind(), change root directory to the given directory by doing a chroot(). This is useful for security, but it restricts the environment a lot. For example, you need to load DBI drivers in the config file or you have to create hard links to Unix sockets, if your drivers are using them. For example, with MySQL, a config file might contain the following lines:
my $rootdir = '/var/dbiproxy';
my $unixsockdir = '/tmp';
my $unixsockfile = 'mysql.sock';
foreach $dir ($rootdir, "$rootdir$unixsockdir") {
mkdir 0755, $dir;
}
link("$unixsockdir/$unixsockfile",
"$rootdir$unixsockdir/$unixsockfile");
require DBD::mysql;
{
'chroot' => $rootdir,
...
}
If you don't know chroot(), think of an FTP server where you can see a certain directory tree only after logging in. See also the --group and --user options.
clients
An array ref with a list of clients. Clients are hash refs, the attributes accept (0 for denying access and 1 for permitting) and mask, a Perl regular expression for the clients IP number or its host name.
configfile (--configfile=file)
Config files are assumed to return a single hash ref that overrides the arguments of the new method. However, command line arguments in turn take precedence over the config file. See the "CONFIGURATION FILE" section below for details on the config file.
debug (--debug)
Turn debugging mode on. Mainly this asserts that logging messages of level "debug" are created.
facility (--facility=mode)
(UNIX only) Facility to use for Sys::Syslog. The default is daemon.
group (--group=gid)
After doing a bind(), change the real and effective GID to the given. This is useful, if you want your server to bind to a privileged port (<1024), but don't want the server to execute as root. See also the --user option.localaddr (--localaddr=ip)
By default a daemon is listening to any IP number that a machine has. This attribute allows one to restrict the server to the given IP number.
localport (--localport=port)
This attribute sets the port on which the daemon is listening. It must be given somehow, as there's no default.
logfile (--logfile=file)
Be default logging messages will be written to the syslog (Unix) or to the event log (Windows NT). On other operating systems you need to specify a log file. The special value "STDERR" forces logging to stderr. See Net::Daemon::Log for details.
mode (--mode=modename)
The server can run in three different modes, depending on the environment.pidfile (--pidfile=file)
(UNIX only) If this option is present, a PID file will be created at the given location. Default is to not create a pidfile.
user (--user=uid)
After doing a bind(), change the real and effective UID to the given. This is useful, if you want your server to bind to a privileged port (<1024), but don't want the server to execute as root. See also the --group and the --chroot options.version (--version)
Suppresses startup of the server; instead the version string will be printed and the program exits immediately.
DBI::ProxyServer is built on RPC::PlServer which is, in turn, built on Net::Daemon.
You should refer to Net::Daemon for how to shutdown the server, except that you can't because it's not currently documented there (as of v0.43). The bottom-line is that it seems that there's no support for graceful shutdown.
The configuration file is just that of RPC::PlServer or Net::Daemon with some additional attributes in the client list.
The config file is a Perl script. At the top of the file you may include arbitrary Perl source, for example load drivers at the start (useful to enhance performance), prepare a chroot environment and so on.
The important thing is that you finally return a hash ref of option name/value pairs. The possible options are listed above.
All possibilities of Net::Daemon and RPC::PlServer apply, in particular
Additionally the server offers you query restrictions. Suggest the following client list:
'clients' => [
{ 'mask' => '^admin\.company\.com$',
'accept' => 1,
'users' => [ 'root', 'wwwrun' ],
},
{
'mask' => '^admin\.company\.com$',
'accept' => 1,
'users' => [ 'root', 'wwwrun' ],
'sql' => {
'select' => 'SELECT * FROM foo',
'insert' => 'INSERT INTO foo VALUES (?, ?, ?)'
}
}
]
then only the users root and wwwrun may connect from admin.company.com, executing arbitrary queries, but only wwwrun may connect from other hosts and is restricted to
$sth->prepare("select");
or
$sth->prepare("insert");
which in fact are "SELECT * FROM foo" or "INSERT INTO foo VALUES (?, ?, ?)".
This section tells you how to restrict a DBI-Proxy: Not every user from every workstation shall be able to execute every query.
There is a perl program "dbiproxy" which runs on a machine which is able to connect to all the databases we wish to reach. All Perl-DBD- drivers must be installed on this machine. You can also reach databases for which drivers are not available on the machine where you run the program querying the database, e.g. ask MS-Access-database from Linux.
Create a configuration file "proxy_oracle.cfg" at the dbproxy-server:
{
# facility => 'daemon',
pidfile => 'your_dbiproxy.pid',
logfile => 1,
debug => 0,
mode => 'single',
localport => '12400',
clients => [
{
mask => '^10\.95\.81\.243$',
accept => 1,
users => [ 'informationdesk' ],
sql => {
alive => 'select count(*) from dual',
statistic_area => 'select count(*) from e01admin.e01e203 where geb_bezei like ?',
}
},
{
mask => '^10\.95\.81\.1$',
accept => 0,
},
{
mask => '^10\.95\.81\.(\d+)$',
accept => 1,
users => [ 'informationdesk', 'lippmann' ],
sql => {
search_city => 'select ort_nr, plz, ort from e01admin.e01e200 where plz like ?',
search_area => 'select gebiettyp, geb_bezei from e01admin.e01e203 where geb_bezei like ? or geb_bezei like ?',
}
},
{
mask => '^10\.95\.81\.5$',
accept => 0,
}
]
}
Start the proxyserver like this:
rem well-set Oracle_home needed for Oracle
set ORACLE_HOME=d:\oracle\ora81
dbiproxy --configfile proxy_oracle.cfg
Call a program "dbish" from your commandline. I take the machine from rule "internal_webserver"
dbish "dbi:Proxy:hostname=oracle.zdf;port=12400;dsn=dbi:Oracle:e01" informationdesk xxx
There will be a shell-prompt:
informationdesk@dbi...> alive
Current statement buffer (enter '/'...):
alive
informationdesk@dbi...> /
COUNT(*)
'1'
[1 rows of 1 fields returned]
Create a perl-script like this:
# file: oratest.pl
# call me like this: perl oratest.pl user password
use strict;
use DBI;
my $user = shift || die "Usage: $0 user password";
my $pass = shift || die "Usage: $0 user password";
my $config = {
dsn_at_proxy => "dbi:Oracle:e01",
proxy => "hostname=oechsle.zdf;port=12400",
};
my $dsn = sprintf "dbi:Proxy:%s;dsn=%s",
$config->{proxy},
$config->{dsn_at_proxy};
my $dbh = DBI->connect( $dsn, $user, $pass )
|| die "connect did not work: $DBI::errstr";
my $sql = "search_city";
printf "%s\n%s\n%s\n", "="x40, $sql, "="x40;
my $cur = $dbh->prepare($sql);
$cur->bind_param(1,'905%');
&show_result ($cur);
my $sql = "search_area";
printf "%s\n%s\n%s\n", "="x40, $sql, "="x40;
my $cur = $dbh->prepare($sql);
$cur->bind_param(1,'Pfarr%');
$cur->bind_param(2,'Bronnamberg%');
&show_result ($cur);
my $sql = "statistic_area";
printf "%s\n%s\n%s\n", "="x40, $sql, "="x40;
my $cur = $dbh->prepare($sql);
$cur->bind_param(1,'Pfarr%');
&show_result ($cur);
$dbh->disconnect;
exit;
sub show_result {
my $cur = shift;
unless ($cur->execute()) {
print "Could not execute\n";
return;
}
my $rownum = 0;
while (my @row = $cur->fetchrow_array()) {
printf "Row is: %s\n", join(", ",@row);
if ($rownum++ > 5) {
print "... and so on\n";
last;
}
}
$cur->finish;
}
The result
C:\>perl oratest.pl informationdesk xxx
search_city
Row is: 3322, 9050, Chemnitz
Row is: 3678, 9051, Chemnitz
Row is: 10447, 9051, Chemnitz
Row is: 12128, 9051, Chemnitz
Row is: 10954, 90513, Zirndorf
Row is: 5808, 90513, Zirndorf
Row is: 5715, 90513, Zirndorf
... and so on
search_area
Row is: 101, Bronnamberg
Row is: 400, Pfarramt Zirndorf
Row is: 400, Pfarramt Rosstal
Row is: 400, Pfarramt Oberasbach
Row is: 401, Pfarramt Zirndorf
Row is: 401, Pfarramt Rosstal
statistic_area
DBD::Proxy::st execute failed: Server returned error: Failed to execute method CallMethod: Unknown SQL query: statistic_area at E:/Perl/site/lib/DBI/ProxyServer.pm line 258.
Could not execute
The most important section to control access to your dbi-proxy is "client=>" in the file "proxy_oracle.cfg":
Controlling which person at which machine is allowed to access
Controlling which SQL-statements are allowed
You can put every SQL-statement you like in simply omitting "sql => ...", but the more important thing is to restrict the connection so that only allowed queries are possible.
If you include an sql-section in your config-file like this:
sql => {
alive => 'select count(*) from dual',
statistic_area => 'select count(*) from e01admin.e01e203 where geb_bezei like ?',
}
The user is allowed to put two queries against the dbi-proxy. The queries are not "select count(*)...", the queries are "alive" and "statistic_area"! These keywords are replaced by the real query. So you can run a query for "alive":
my $sql = "alive";
my $cur = $dbh->prepare($sql);
...
The flexibility is that you can put parameters in the where-part of the query so the query are not static. Simply replace a value in the where- part of the query through a question mark and bind it as a parameter to the query.
my $sql = "statistic_area";
my $cur = $dbh->prepare($sql);
$cur->bind_param(1,'905%');
# A second parameter would be called like this:
# $cur->bind_param(2,'98%');
The result is this query:
select count(*) from e01admin.e01e203
where geb_bezei like '905%'
Don't try to put parameters into the sql-query like this:
# Does not work like you think.
# Only the first word of the query is parsed,
# so it's changed to "statistic_area", the rest is omitted.
# You _have_ to work with $cur->bind_param.
my $sql = "statistic_area 905%";
my $cur = $dbh->prepare($sql);
...
RPC::PlServer used underneath is not secure due to serializing and deserializing data with Storable module. Use the proxy driver only in trusted environment.
Copyright (c) 1997 Jochen Wiedmann
Am Eisteich 9
72555 Metzingen
Germany
Email: joe AT ispsoft.de
Phone: +49 7123 14881
The DBI::ProxyServer module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. In particular permission is granted to Tim Bunce for distributing this as a part of the DBI.
dbiproxy, DBD::Proxy, DBI, RPC::PlServer, RPC::PlClient, Net::Daemon, Net::Daemon::Log, Sys::Syslog, Win32::EventLog, syslog
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2026-08-25 05:21 @216.73.216.179
CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)