Sep 21, 2009

DHCP on PCs: Lease-Time

Everyone knows DHCP. Yes your PC gets something like a lease for a time...
Do you know how to ask your PC, when this lease expires?
This is not very difficult:
On Windows:
ipconfig /all

Ethernetadapter Drahtlose Netzwerkverbindung:

Verbindungsspezifisches DNS-Suffix:
Beschreibung. . . . . . . . . . . : Intel(R) PRO/Wireless 2200BG Network Connection
Physikalische Adresse . . . . . . : 00-12-34-56-78-90
DHCP aktiviert. . . . . . . . . . : Ja
Autokonfiguration aktiviert . . . : Ja
IP-Adresse. . . . . . . . . . . . :
Subnetzmaske. . . . . . . . . . . :
Standardgateway . . . . . . . . . :
DHCP-Server . . . . . . . . . . . :
DNS-Server. . . . . . . . . . . . :
Lease erhalten. . . . . . . . . . : Dienstag, 22. September 2009 20:58:40
Lease läuft ab. . . . . . . . . . : Freitag, 2. Oktober 2009 20:58:40
On Linux:
cat /var/lib/dhcp3/dhclient.leases
lease {
interface "eth1";
option subnet-mask;
option routers;
option dhcp-lease-time 864000;
option dhcp-message-type 5;
option domain-name-servers;
option dhcp-server-identifier;
option dhcp-renewal-time 432000;
option ntp-servers;
option broadcast-address;
option dhcp-rebinding-time 756000;
option domain-name "";
renew 6 2009/09/26 15:58:34;
rebind 3 2009/09/30 12:17:44;
expire 4 2009/10/01 18:17:44;
This is ok, but what if you use a black box as router, where you can not adjust the dhcpd parameters? Something like changing the lease time, because 756000s=210h=8.75d is really to long for a network, where you use computers only on a hourly base...
On Linux you can configure your client very easy:
Add inside /etc/dhclient.conf the following line
send dhcp-lease-time 3600;
After this little change start dhcp with
dhclient -cf /etc/dhclient.conf
and your lease details show:
option dhcp-lease-time 3600;
option dhcp-renewal-time 1800;
option dhcp-rebinding-time 3150;
On Windows this is nearly impossible:
There is a nice starting point provided by Microsoft: But with this information you only know that you have to add the following key inside the registry:
With the explanation given there
Lease Time (51): This option is used in a client request (DHCPDISCOVER or DHCPREQUEST) to allow the client to request a lease time for the IP address. In a server reply (DHCPOFFER), a DHCP server uses this option to specify the lease time it is willing to offer. The time is in seconds, and is specified as a 32-bit unsigned integer. The code for this option is 51, and its length is 4.
it is not possible without any futher documentation to create the appropriate keys and values ... ;-(

Sep 18, 2009

Sun's hardware at Oracle: cont'd

After my last posting there was another announcement from Oracle regarding SUN hardware and Oracle software:

At the full presentation is provided by Oracle.
Please note that Exadata Version 2 consists of
x86 CPU cores
So Oracle does not only commit the SUNs SPARC architecture...

Sep 11, 2009

Sun's hardware at Oracle: a new announcement

Oracle announced the following statement on their website:

But why did they announce this now?
Here some answers out of the web:
The advertisement is a sign of how seriously Oracle views the Sun customer base as part of the value of Sun. At JavaOne, Ellison said Oracle has sold many database systems to run on Sun servers. Linux servers make up its fastest growing business, but Sparc/Solaris platforms remain its largest installed base, he said.
Analysts see Oracle's ad as a defensive move ... Among the top hardware makers, Sun registered the biggest decline in server revenue in the second quarter, offering evidence that this protracted merger may be eroding Sun's value.
Still, this may all be a little propaganda to ease the worries of the EU's Competition Commission, which has extended its investigation of the deal.
This is very good news for us geeks; Oracle is promising to invest in not only Solaris, some decent competition for Linux, but also in the SPARC architecture. We're getting two alternative products for one here.
Many opinions and if you ask yourself, you will get even more ;-)

Sep 9, 2009

Oracle SOA Suite 11g: How to start the soa instance...

You tried to install Oracle's SOA Suite 11g?
The installation completed successfully?
You got the login screen like shown in this posting?

Now you can login...

The next screen shows this:

After that there is this fancy gui with some flash components inside:

Yippie! Everything is ok...
Let's take a look at the SOA components:

But stop! There are no SOA components. The manual shows this:

How do i get this additional folder inside the SOA console?
Ok, this is very easy:
/opt/Oracle/Middleware/user_projects/domains/soa_domain/bin/ soa_server1 http://localhost:7001
And here we go:

Just a last comment: Stopping this server can be done via command:
./ soa_server1 t3://hades:7001 weblogic oracle10

Sep 8, 2009

Oracle WLS: Installation errors

Did you try to install an Oracle WLS and got some errors like:
and you do not know what to do?
The official pages are here. There you can find some explanations.
For the errors abouve, the provided Middleware home was empty....