Tag Archives: debian

PostgreSQL 8.3 adding uuid-ossp on Debian

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UUID is a nice way to generate (almost) unique id’s.

However on PostgreSQL 8.3 the data type exists, but if you wish to be able to generate UUID’s you need to get a module (in this case uuid-ossp).

On Debian this module is in the contrib package, so if you have not installed this before do it now

user@server:~$ sudo apt-get install postgresql-contrib

Then you need to “load” the module into PostgreSQL; or more accurately you tell PostgreSQL about the new functions this module has, how to reach them etc.
Depending on you security settings (in pg_hba.conf) you may need to log in as the postgres user on your system.

postgres@sever:~$ psql -d MYDB -U postgres -f /usr/share/postgresql/8.3/contrib/uuid-ossp.sql

apt-get WARNING: The following packages cannot be authenticated!

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apt-get is verifying the packages before installing them.
If the keys are not up to date, then apt-get upgrade will issue a warning.

WARNING: The following packages cannot be authenticated!
  ure uno-libs3
Install these packages without verification [y/N]?

The way to solve this is rather simple, just run apt-get update and it should download the keys automatically.

apt-key handles keys, using apt-key list will show you the keys that are on the computer.

apt-get update The following packages have been kept back

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 apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
  bind9-host dnsutils libbind9-50 libdns50 libisc50 libisccc50 libisccfg50 liblwres50 linux-generic linux-generic-pae linux-image-generic
  linux-image-generic-pae
0 upgraded, 0 newly installed, 0 to remove and 12 not upgraded.

The message has been kept back most often means that the upgrade was kept back due to dependencies that are not met.

Some possible solutions

  • A simple way is to invoke dselect to help out with the update. dselect performs the actions necessary to realize that state (for instance, the removal of old and the installation of new packages). 
     apt-get dselect-upgrade
  • While apt-get and aptitude are basically the same, aptitude is sometimes better at handling dependencies than apt-get 
     aptitude upgrade
  • Another solution is to install the package using apt-get install to install the upgraded package and let apt-get install the missing dependencies 
     apt-get install dnsutils

Quickly configure shorewall on Debian

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By definition shorewall is not a firewall, it is a way to (more) easily configure iptables to work as a firewall.

  • First install shorewall “$ apt-get intall shorewall”
  • Enter /etc/shorewall
  • Copy the example files from /usr/share/doc/shorewall-common/default-config/ (might also be located in /usr/share/doc/shorewall/default-config/) “$ cp /usr/share/doc/shorewall-common/default-config/* .”
  • Edit the files and enter the data that your system has
    • First create zones “$ nano zones” 
       #ZONE   TYPE            OPTIONS         IN OPTIONS                OUT OPTIONS
fw      firewall
net     ipv4
vpn     ipv4
    • Connect zones with interfaces”$ nano interfaces” 
       #ZONE   INTERFACE       BROADCAST       OPTIONS
net     eth0            detect          tcpflags,blacklist,dhcp
vpn	tun0		-
    • Create policies “$ nano policy” 
       #SOURCE         DEST            POLICY          LOG LEVEL       LIMIT:BURST
fw              net             ACCEPT
vpn             net             ACCEPT
vpn             fw              ACCEPT
fw              vpn             ACCEPT
net             all             DROP            info
all             all             DROP            info
    • Create rules “$ nano rules” 
       #ACTION SOURCE          DEST            PROTO   DEST    SOURCE          ORIGINAL        RATE            USER/
#                                               PORT(S) PORT(S)         DEST            LIMIT           GROUP
ACCEPT          net             fw             tcp     22 # ssh
ACCEPT          net             fw             tcp     80 # web
    • Verify that the rules are fine “$ shorewall check”
    • Edit /etc/default/shorewall and set startup to 1 
       # prevent startup with default configuration
# set the following varible to 1 in order to allow Shorewall to start
 
startup=1
    • Start the firewall “$ /etc/init.d/shorewall start”

If you later decide to update rules, zones etc run “$ /etc/init.d/shorewall restart” to load the changes.

Memtest86+ in grub

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Turns out using Debian it is very simple to get memtest86+ to appear in the grub boot up menu.

Simply install it as usual using apt-get.

After the installation is complete do a grub-install.

That’s it, after rebooting memtest86+ is now in the grub menu.

(Now how come it was not possible to google out  this info;) )