Humber's questions

I'm using PostgreSQL 8.3 under ubuntu 9.04. I access my database server using a console client or Pgadmin III. Currently, I need to restrict access to only a couple of schemas in a database and also don't show other databases in the server.

For example, my current postgres server has the following databases:

postgres-8.3-server
|-- db1
|   |-- sch_a
|   |-- sch_b
|   |-- sch_c
|   `-- sch_d
|-- db2
|   |-- sch_e
|   |-- sch_f
|   `-- sch_g
`-- db3
    `-- sch_h

I need to restrict role "joe" to access only db2's sch_e and shc_g, and also don't show the other schemas in the same database. When listing databases the output should be:

postgres-8.3-server
|-- db2
    |-- sch_e
    `-- sch_g

My current solution restricts schema and database access but I can still see the database name list. When I try to access any of them (except the one I'm allowed to) I receive a message about a specific entry not found at pg_hba.conf file, which is good but not ideal.

I'm currently checking the manual and googling for more information.

Thanks in advance

I was looking for a method to restrict access to a private Debian repository and be able to authenticate to it non-interactively (i.e. using a script)

The most useful article I found if actually one from Debian administration site but the secure method uses ssh and public/private keys. It works great but each host's public key needs to be inside the remote authorized_keys file to successfully authenticate. It doesn't says nothing about providing password to ssh:// but I suppose it should be possible.

Have you tried other alternatives (e.g. ftps)?

Thanks in advance

Do you have some recommendations on setting up a MANET using Debian based OS? I read some documentation after some web digging and I found that a basic setup would be creating an ad-hoc wireless network and some routing algorithms (implementation) as:

• OLSR (Optimized Link State Routing protocol):
• OSPF (Open Shortest Path First Routing)
• B.A.T.M.A.N. (Better Approach To Mobile Adhoc Networking)
• AODV (Ad hoc On-Demand Distance Vector)

I'm currently starting to test some of them (currently B.A.T.M.A.N :D) but haven't finish any of them. I got really inspired after seeing open-mesh.com project/products (it looks like they use ROBIN and B.A.T.M.A.N).

Thanks in advance!

Note: I'm a complete newbie at this so I apologize if some terms/concepts aren't correct. All feedback will be appreciated

Do you have any experience/scrips creating a controlled APT proxy (*)? Currently, I'm using apt-cacher to speed up installs/updates in my LAN, but as its name says, it's only a cache (and a good one for my needs). The only drawback is that I don't know how to freeze a specific set of packages for the cache/repository to control updates. Almost certainly, apt-cacher isn't the right tool for this jobs so, any help would be appreciated.

Thanks in advance,

Humber

(*) An APT repository that has only specific packages and updates to control the OS that uses that repository. I named this way because I don't know if it has another name

Does somebody knows how to clone/connect to a running xorg server to see in soft real time what is the monitor/display showing (The display is a couple of miles away but I can reach it throw TCP/IP)? I have a small script to get a screenshot but is a bit limited.

#!/bin/bash
REMOTE_USER=root
IP=$1
IMAGE_FILE=/tmp/host_${IP}_`date +"%Y%m%d-%H:%M:%S"`.png
ssh root@$IP 'xwd -d :0 -root | gzip' | gunzip | convert - $IMAGE_FILE

I thought that it would be nice to see what the display is showing in soft real time, if possible of course. :)

Thanks in advance,

Humber

I would like to execute a bash script after a TUN driver (e.g. tun0) is up under ubuntu 9.04/9.10. I need it to use the assigned VPN IP in some configuration scripts. Do you have any suggestion?

Thanks in advance,

Humber

How can I check if a bootloader (i.e. grub2) is installed on a block device (e.g. CF card)? I know I can mount the device and peek some files but how can I be sure the bootloader is installed without having to test it (try to boot it on some device) Thanks in advance

Do you have a clean/nice way to only start Xorg server under Ubuntu 9.04 and be able to start/stop it? Something like:

# /etc/init.d/xorg start

I have an application that doesn't use a window manager (uses Xorg directly) that starts after boot (Now just uses startx directly). I have an skeleton for it:

case "$1" in
  start)
    echo "Starting xorg... "
    # code for start
    ;;
  stop)
    echo "Stopping xorg..."
    # code for stop
    ;;
  *)
    echo "Usage: /etc/init.d/xorg {start|stop}"
    exit 1
    ;;
esac
exit 0

But it would be nice if somebody can give me a proven (complete) script. Thanks in advance!

First, the working scenario. One OpenVPN client (2.1~rc11 under ubuntu 9.04) connects to a OpenvPN server (2.1~rc11 ubuntu 8.10) using a ethernet interface (eth0). Both use TUN device and UDP connection. But when I turn on the wireless interface (ifup wlan0) in the client ,the host can't communicate with the server anymore. I read a bit about the problem but didn't found a working solution. Maybe setting some iptable rules to mark the incoming datagrams to output them through the same interface. Any help would be appreciated.

Thanks in advance