Edit /etc/sysconfig/network inserting:

HOSTNAME=xxx.machine

Restart.

Oracle E-Business Suite is not dependent to IP address, so one can easily change the IP address of nodes without any effect on E-Business Suite.

What about Hostname, Domain and Ports? Oracle E-Business Suite is dependent to these. So, we couldn’t change theme without coordination of E-Business Suite itself.

There are two methods for changing Hostname, Domain and Ports of Oracle E-Business Suite. The first method, that will be discussed here, is using autoconfig and another method is by cloning. It is easier to use autoconfig method to change hostname, domain and ports and use cloning method for changing other configurations of Oracle E-Business Suite.

In this document we assume that our E-Business Suite has just one node so that all Tiers and Servers reside on this node. For changing hostname, domain and ports of a multinode Oracle E-Business Suite, refer to the documents listed in the refrences section of this post.

1.   DB Tier: Deregister the current database server

As the database hostname and domain will be changed, the current database server node needs to be de-registered.

SQL> select NAME, SERVER_TYPE from FND_APP_SERVERS, FND_NODES

where FND_APP_SERVERS.NODE_ID = FND_NODES.NODE_ID and

SERVER_TYPE='DB' and FND_NODES.NODE_NAME=UPPER('oldhost');

NAME            SERVER_TYPE

--------------- -----------

oldhost_PROD_DB  DB

# cd $ORACLE_HOME/appsutil

# perl ./bin/adgentns.pl appspass=<APPSpwd> contextfile=./PROD_oldhost.xml -removeserver

SQL> select NAME, SERVER_TYPE from FND_APP_SERVERS, FND_NODES

where FND_APP_SERVERS.NODE_ID = FND_NODES.NODE_ID and

SERVER_TYPE='DB' and FND_NODES.NODE_NAME=UPPER('oldhost');

no rows selected

2.   DB Tier: Create a new Context file

You can create the new context file using whichever of the following methods:

a. Manuall Method:

# cd $ORACLE_HOME/appsutil

# cp PROD_oldhost.xml PROD_newhost.xml

Edit PROD_newhost.xml manually:

Replace all oldhost with newhost

Replace all olddomain with newdomain

b. Script Method:

# cd $ORACLE_HOME/appsutil

# perl ./bin/adclonectx.pl contextfile=./PROD_oldhost.xml

Provide the values required for creation of the new Database Context file.

Do you want to use a virtual hostname for the target node (y/n) [n] ?:

Target hostname [oldhost]:newhost

Target System database name [PROD]:

Target instance is a Real Application Cluster (RAC) instance (y/n) [n]:

Target system domain name [olddomain]:newdomain

Oracle OS User [oraprod]:

Oracle OS Group [dba]:

Target system RDBMS ORACLE_HOME directory [/gldb/apps/d02/oracle/proddb/9.2.0]:

Target system utl_file accessible directories list [/usr/tmp]:

Number of DATA_TOP's on the target system [4]:1

Target system DATA_TOP 1:/gldb/apps/d03/oracle/proddata

Do you want to preserve the Display set to oldhost:0.0 (y/n) [y] ?:n

Target system Display [newhost:0.0]:

Target system JAVA_TOP location [null]:/gldb/apps/d01/oracle/prodcomn/java

Do you want to preserve the port values from the source system on the target system (y/n) [y] ?:

Database port is 1521

New context path and file name [PROD_newhost.xml]:

Creating the new Database Context file from :

/gldb/apps/d02/oracle/proddb/9.2.0/appsutil/template/adxdbctx.tmp

The new database context file has been created :

/gldb/apps/d02/oracle/proddb/9.2.0/appsutil/PROD_newhost.xml

Note: The command above will create a new Context file of the format PROD_newhost.xml in the current working directory.

3.   APPS Tier: Deregister the current Applications server

As the Applications hostname and domain will be changed, the current Applications server node needs to be de-registered.

SQL> select NAME, SERVER_TYPE from FND_APP_SERVERS, FND_NODES

where FND_APP_SERVERS.NODE_ID = FND_NODES.NODE_ID and

SERVER_TYPE='APPS' and FND_NODES.NODE_NAME=UPPER('oldhost');

NAME              SERVER_TYP

----------------- ----------

oldhost_PROD_APPS  APPS

# cd $APPL_TOP/admin

# perl $AD_TOP/bin/adgentns.pl appspass=<APPSpwd> contextfile=./PROD_oldhost.xml -removeserver

SQL> select NAME, SERVER_TYPE from FND_APP_SERVERS, FND_NODES

where FND_APP_SERVERS.NODE_ID = FND_NODES.NODE_ID and

SERVER_TYPE='APPS' and FND_NODES.NODE_NAME=UPPER('oldhost');

no rows selected

4.   APPS Tier: Create a new Context file

You can create the new context file using whichever of the following methods:

a. Manuall Method:

# cd $APPL_TOP/admin

# cp PROD_oldhost.xml PROD_newhost.xml

Edit PROD_newhost.xml manually:

Replace all oldhost with newhost

Replace all olddomain with newdomain

b. Script Method:

# cd $APPL_TOP/admin

# perl $AD_TOP/bin/adclonectx.pl contextfile=./PROD_oldhost.xml

Provide the values required for creation of the new APPL_TOP Context file.

Do you want to use a virtual hostname for the target node (y/n) [n] ?:

Target hostname [oldhost]:newhost

Target system database SID [PROD]:

Target system domain name [olddomain]:newdomain

Username for the applications file system owner [applprod]:

Group for the applications file system owner [dba]:

Target system database server node [oldhost]:newhost

Does the target system have more than one application tier server node (y/n) [n] ?:

Is the target system APPL_TOP divided into multiple mount points(y/n)[n]?:

Target system APPL_TOP mount point [/gldb/apps/d01/oracle/prodappl]:

Target system COMMON_TOP directory [/gldb/apps/d01/oracle/prodcomn]:

Target system 8.0.6 ORACLE_HOME directory [/gldb/apps/d01/oracle/prodora/8.0.6]:

Target system iAS ORACLE_HOME directory [/gldb/apps/d01/oracle/prodora/iAS]:

Do you want to preserve the Display set to oldhost:0.0 (y/n) [y] ?:n

Target system Display [newhost:0.0]:

Location of JDK 1.3.1 on the target system [/usr/java14]:

Do you want to preserve the port values from the source system on the target system (y/n) [y] ?:

Web Listener port is 8000

Complete port information available at /gldb/apps/d01/oracle/prodappl/admin/out/PROD_newhost/portpool.lst

New context path and file name [PROD_newhost.xml]:

Creating the new APPL_TOP Context file from :

/gldb/apps/d01/oracle/prodappl/ad/11.5.0/admin/template/adxmlctx.tmp

The new APPL_TOP context file has been created :

/gldb/apps/d01/oracle/prodappl/admin/PROD_newhost.xml

Note: The command above will create a new Context file of the format PROD_newhost.xml in the current working directory.

5.   APPS Tier: Shutdown the Application Tier Services

# $COMMON_TOP/admin/scripts/PROD_oldhost/adstpall.sh apps/<appspasswd>

6.   Change the hostname and domain

Change the hostname and domain at OS level.

# hostname -s newhost

# edit /etc/hosts as follow:

OLD: IP-Address     oldhost.olddomain     oldhost

NEW: IP-Address     newhost.newdomain     newhost

7.   DB Tier: Reseed the Net Services Topology Model

# cd $ORACLE_HOME/appsutil

# ./bin/adconfig.sh contextfile=./PROD_newhost.xml

8.   APPS Tier: Reseed the Net Services Topology Model

The Net Services Topology Model is automatically updated by running AutoConfig.

# $AD_TOP/bin/adconfig.sh contextfile=$APPL_TOP/admin/PROD_newhost.xml appspass=<appspasswd>

9.   DB Tier: Shutdown the database and listener

# $ORACLE_HOME/appsutil/scripts/PROD_oldhost/addbctl.sh stop

# $ORACLE_HOME/appsutil/scripts/PROD_oldhost/addlnctl.sh stop PROD

10.  DB Tier: Start the listener and database

# $ORACLE_HOME/appsutil/scripts/PROD_newhost/addlnctl.sh start PROD

# $ORACLE_HOME/appsutil/scripts/PROD_newhost/addbctl.sh start

11.  APPS Tier: Start the Application Tier Services

# $COMMON_TOP/admin/scripts/PROD_newhost/adstrtal.sh apps/<appspasswd>

Notes:

1. Q: Do you encounter the following errors when you start the listener?

Error listening on: (ADDRESS=(PROTOCOL=TCP)(Host=newhost)(Port=1521))

TNS-12532: TNS:invalid argument

TNS-12560: TNS:protocol adapter error

TNS-00502: Invalid argument

IBM/AIX RISC System/6000 Error: 515: Error 515 occurred.

  A: Check $ORACLE_HOME/network/admin/PROD_newhost/sqlnet.ora to insure it is using new values:

OLD: tcp.invited_nodes=(oldhost.olddomain, newhost.newdomain)

NEW: tcp.invited_nodes=(newhost.newdomain)

     2.  Q: Do you encounter the following errors in Jinitiator console when you try to start form applications?

java.lang.NoClassDefFoundError: org/apache/regexp/RESyntaxException

at oracle.ewt.lwAWT.lwText.LWTextField.getText(LWTextField.java:196)

at oracle.ewt.lwAWT.lwText.LWTextField._getDisplayString(LWTextField.java:787)

A: Check $OA_HTML/bin/appsweb_PROD_newhost.cfg for the value of ‘archive2′. It should be as follow:

archive2=,/OA_JAVA/regexp.jar

     3.  Q: Do you encounter the following errors in Jinitiator console when you try to start form applications?

java.lang.Error: RE internal error: Corrupt program

at org.apache.regexp.RE.internalError(RE.java:820)

at org.apache.regexp.RE.matchNodes(RE.java:1414)

A: Made the following change:

# cd $JAVA_TOP

# mv org org.back

 References:

1. How to change the hostname of an Applications Tier using AutoConfig [Metalink 341322.1]

2. How to change the hostname and/or port of the Database Tier using AutoConfig [Metalink 338003.1]

Ever wanted to name a server with amazon-ec2 naming convention?
I hope not!

If anyone wondered what is the max length of hostname you can use (solutions and guess over the internet already), but just itching to write down how to find out. Here’s how..

krish@lin-hyd-dsk-07:~> getconf HOST_NAME_MAX
64

This is defined in file
krish@lin-hyd-dsk-07:~> grep HOST_NAME_MAX /usr/include/bits/local_lim.h
#define HOST_NAME_MAX 64

The Single Unix Specification version 2 (SuSv2) guarantees ‘Host names are limited to 255 bytes’. POSIX 1003.1-2001 guarantees ‘Host names (not including the terminating NULL) are limited to HOST_NAME_MAX bytes’.

How to change the hostname under Fedora?

Use the command line (terminal)

First, loggin’ like root

[user@machine ~]$ su – root
Password: blah blah blah

Second type the “hostname” command to look your actually hostname

[root@machine ~]# hostname
machine

Now, just type hostname test.somedomain.ac.cr
[root@machine ~]# hostname test.somedomain.ac.cr

Now, you can look your new hostname with same command

[root@machine ~]# hostname
test.somedomain.ac.cr

This is temporaly, not is permanent, to be a change permanent you need to backup and edit some files..

Let’s do it!

backup /etc/sysconfig/network
[root@machine ~]# cp -p /etc/sysconfig/network /etc/sysconfig/network.bak

look what is in to original file
[root@igor ~]# cat /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=machine
[root@igor ~]#

now edit the original file
[root@igor ~]# vi /etc/sysconfig/network

NETWORKING=yes
HOSTNAME=mahine # In my case I’ll put “test.somedomain.ac.cr”
# Edit and save

To test the new line
[root@machine ~]# grep HOSTNAME /etc/sysconfig/network
HOSTNAME=test.somedomain.ac.cr
[root@machine ~]#

Now backup and edit /etc/hosts
[root@machine ~]# cp -p /etc/hosts /etc/hosts.bak
[root@machine ~]#

Look what is into /etc/hosts file:
[root@machine ~]# cat /etc/hosts
# hostname machine added to /etc/hosts by anaconda
127.0.0.1        localhost.localdomain localhost machine
::1        localhost6.localdomain6 localhost6 machine

Now edit the line
[root@machine ~]# vi /etc/hosts
# I just change in my case the word “machine” in the three lines for “test.somedomain.ac.cr”
# edit and save
# hostname test.somedomain.ac.cr added to /etc/hosts by anaconda
127.0.0.1        localhost.localdomain localhost test.somedomain.ac.cr
::1        localhost6.localdomain6 localhost6 test.somedomain.ac.cr
[ravs@igor ~]$

Test it
[root@machine ~]# cat /etc/hosts
# hostname test.somedomain.ac.cr added to /etc/hosts by anaconda
127.0.0.1        localhost.localdomain localhost test.somedomain.ac.cr
::1        localhost6.localdomain6 localhost6 test.somedomain.ac.cr

and the final step restart the service network

[root@machine ~]# service network restart
Shutting down interface eth0:                              [  OK  ]
Shutting down interface eth1:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:                                [  OK  ]
Bringing up interface eth1:                                [  OK  ]
[root@machine ~]#

now log out, and loging again!!

that’s it!

Tested on Fedora 12 Gnome – 2.6.31.5-127.fc12.i686 GNU/Linux

You may encounter this message while connecting to a remote server through ssh.
Generally, you also have these lines :

IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is

To prevent from having this error again, there are solutions :

1) Edit the following line  ~/.ssh/known_hosts and remove the line containing the hostname of the remote server in question.

2) Sometime, the file ~/.ssh/known_hosts may be hashed. To regenerate the key properly,as a non-root user, please type the following command :

fool@localhost:~$ ssh-keygen -R hostname

We use the OpenVPN module in the Untangle Open Source Network Gateway for remote access at our school district.   Everything had been working flawlessly for over a year until suddenly right before I was set to leave for a two day conference, I turned on my Windows 7 RC1 Acer Aspire One netbook, fired up the OpenVPN GUI client and then proceeded to fail at connecting to my remote clients using RDP.    I immediately checked my desktop Windows 7 RC1 install and found the same problem.  Long story short, somehow I had lost the ability to resolve my hostnames  to their correct private IP addresses while connected to the VPN.  The work around for my trip was to connect using IP addresses, which I duly noted before leaving.

Upon my return I decided to troubleshoot the problem.  I was able to rule out a server side issue because 1) no settings had changed since the last time it worked and 2) my Hackintosh OS X desktop system running the OpenVPN client Viscosity worked just fine.  So to rule out my netbook as the culprit, I dusted off my old Dell Inspiron 6400 laptop, which is also running Windows 7 RC1, and tried the OpenVPN GUI client on it.  I got the same frustrating thing, the VPN client connected fine, I just couldn’t resolve my internal DNS names correctly.  I was wondering if this was a problem with the OpenVPN client I was running (2.1rc15) or what else could have possibly changed on both these systems to have this affect.  I decided to try my last instance of Windows 7 RC1 and so fired up Virtual Box on my Hackintosh, started OpenVPN GUI and was pleasantly surprised to connect right away with RDP using my internal hostnames (fully qualified, of course).

Now I knew it was something with Windows 7 on both my desktop, netbook and laptop.  But what could be affecting all three?  Many moons ago, Windows used to have odd problems associated with NIC binding orders.  I happened to notice in the ipconfig dump on the Virtual Box host that the TAP-Win32 adapter was listed first and as this was the NIC with the correct DNS settings to resolve my internal hostnames it looked like something I should check on the other systems.  Sure enough the desktop, netbook and laptop all had the TAP NIC listed in second place when I ran ipconfig /all.  Ah ha!  A quick google search for how to change Windows 7 NIC bindings (not where it used to be) turned up this gem from dillonator:

Get to the Network Connections page under the control panel. (If you’re looking at the Network and Sharing Center, click on Change Adapter Settings.) Now hit the “alt” key and you should see the menu pop up. Click on Advanced and you should know where you’re going from there

I love the fact that you have to press the ALT key to see the advanced settings options.  After moving my TAP-Win32 adapter (Local Area Connection 3) on my desktop to the top of the Connections list I was once again able to RDP into my remote hosts using their fully qualified domain names (FQDN).

I have no idea why or how the binding orders on three of my four Windows 7 RC1 installations changed or why my Virtual Box host was unaffected but I am happily VPNing with OpenVPN once more.   Any ideas on how this might have happened, please leave a comment.  Thanks.

Tutorial Monitoring Jaringan Komputer Menggunakan Look@LAN

ABSTRAK

Look@LAN merupakan salah satu  perangkat lunak (software)  yang dapat digunakan untuk melihat komputer (host) pada suatu jaringan komputer lokal atau sering disebut dengan local area network (LAN), sehingga kita dapat melihat active services atau fasilitas-fasilitas yang disediakannya.

Look@LAN menyediakan beberapa fasilitas untuk melihat  IP Address, status, distance, operating system yang digunakan, hostname, netBIOS name, netBIOS user, SNMP status dan Trap. Informasi host yang sedang online/offline, operating system yang digunakan, NetBIOS dan SNMP yang ditampilkan dalam bentuk grafik.

Berdasarkan hasil yang pernah penulis lakukan, Look@LAN  hanya dapat digunakan untuk melihat komputer yang terhubung pada jaringan lokal, sehingga tidak dapat digunakan untuk jaringan yang lebih luas. Untuk jaringan yang lebih luas, salah satu software yang pernah penulis gunakan adalah NetworkView.

OBA (Oracle Business Accelerator) is a relatively new product from Oracle Corp. It aim to boost up the setup process time of Oracle Applications via online questionnaire within a timeframe called Project Work Space (PWS). Once all question is submitted, then you can download the Setup Configuration Tool from Oracle Application that connect directly, wth the authetication system using approved CSI number, etc.

After you download the file, then you must continue the automated setup process. During the setup process, this tool will warn user about setup that need to be fixed, and you can choose to fix or to skip it. This process relatively take some workingdays. Once the automated Setup Configuration Tool is finished, the tools will provide you links about statistics in hours & minutes; what happened during the process; Errorred process; setup that you need to investigate and check again or setup that failed and need manual setup.

One of the error during running the config tool is s_display value in $CONTEXT_FILE doesn’t match the vnc or xmanager display value.
Once corrected, you’ll be told to run AUTOCONFIG and resume the Setup Configuration Tool. This error cannot be skipped as the Setup Config Tool will prompt you the same error message each time you resuming.

I checked inside the context file (Application context file, NOT the Database context file since display should have nothing related with the database). The value of s_display is already correct =[hostname]:1.0 ( Read metalink note 467549.1 ) the hostname is the server’s IP address.

You could do the trick using a broadcast and Xstart (from Xmanager) or from VNCviewer these application type is different from application like putty, WinSCP or secureCRT. Using Putty for example, when you close the window, your session is “over” in the server, but using VNCviewer, eventhough you have shutdown your PC, then if you login again, your server session is still “alive” unless you have issued command such as logout or reboot.

The trick is simple,  using VNC viewer, open a terminal then login using root. type :

$ export DISPLAY=[your_server_hostname]:1.0

$ xhost +

or

$ xclock

if the clock is displayed then you have done right, just shutdown apps services, run autoconfig and resume the Configuration Setup Tool.

note : to detemine your_server_hostname value, just type hostname in the terminal, the result is what should be set as s_display environment variable value in the $CONTEXT_FILE.

Όσοι γνωρίζουν από δίκτυα ξέρουν ότι η κορυφαία εταιρεία σε εξοπλισμό δικτύων (router,switches κτλ) είναι η Cisco.Είναι λοιπόν ουσιώδες να γνωρίζουμε το πως θα μπορέσουμε να ρυθμίσουμε έναν cisco router αν η ενασχόληση μας είναι η διαχείριση δικτύων.

Router Modes

Ένα Cisco Router έχει αρκετά modes (καταστάσεις) αλλά οι πιο σημαντικές που πρέπει κάποιος να γνωρίζει και να είναι σε θέση να αναγνωρίσει είναι οι παρακάτω:

Router>        —-> User Mode

Router#        —-> Privilege Mode

Router (config)# —–> Global Configuration Mode

Router (config-if)#        ——> Interface Mode

Router (config-subif)#    —–> Subinterface Mode

Router (config-line)#     —-> Line mode

Router (config-router)# —-> Router Configuration Mode

Θα πρέπει να γνωρίζουμε επίσης ότι δεν δουλεύουν όλες οι εντολές σε όλα τα mode.

Global Configuration Mode

Όταν κάνουμε εκκίνηση έναν Cisco Router η πρώτη κατάσταση είναι το User Mode.Στο UserMode δεν μπορούμε να κάνουμε ρυθμίσεις στο router και το μόνο που μπορούμε είναι να δούμε κάποια από τα configurations.

Πληκτρολογώντας την εντολή enable μπαίνουμε στο privilege mode.Σε αυτήν την κατάσταση μπορούμε να δούμε όλα τα configurations που έχουνε γίνει στο router αλλά και να πληκτρολογήσουμε την εντολή configure terminal η οποία και θα μας εισάγει στο Global Configuration Mode όπου και θα μπορέσουμε να ρυθμίσουμε τον router μας.

Παράδειγμα:

Router>

Router>enable

Router# configure terminal

Router(config)#

Ρυθμίζοντας το όνομα του Router

Η εντολή που θα χρειαστούμε για να ρυθμίσουμε το όνομα του router μας είναι να πληκτρολογήσουμε ενώ είμαστε στο Global Configuration Mode το hostname και το όνομα του router μας.Δηλαδή:

Router (config)#hostname datalibrary

Datalibrary (config)#

Ρύθμιση του Serial Interface

Σε περίπτωση που είμαστε σε μία εταιρεία και μας ζητηθεί να συνδέσουμε τον router μας με κάποιον άλλον router της εταιρείας σε κάποια άλλη πόλη ή χώρα τότε θα πρέπει να γνωρίζουμε το πως θα ρυθμίσουμε το serial interface του.

Αν δεν ξέρουμε όμως ποιά είναι τα interface του router που έχουμε τότε η εντολή show ip interface brief στο privilege mode θα μας εμφανίσει όλα τα διαθέσιμα interface του.Δηλαδή:

Router# show ip interface brief

Έτσι λοιπόν η ρύθμιση του Serial interface γίνεται ως εξής:

Router (config)# interface s0/0

Router (config-if)# description Syndesi me ton ISP

Router (config-if)# ip address 192.168.10.1 255.255.255.0

Router (config-if)# clock rate 56000

Router (config-if)#no shutdown

Η εντολή interface s0/0 χρησιμοποιείται για να μπούμε στο interface που θέλουμε να ρυθμίσουμε που στην προκειμένη περίπτωση είναι το s0/0.Έπειτα βλέπουμε την εντολή description μαζί με ένα μήνυμα η οποία δίνει μία περιγραφή στο interface.Η εντολή αυτήν είναι προεραιτική αλλά αρκετά χρήσιμη σε περίπτωση που έχουμε πολλά interface για να ξέρουμε ποιό συνδέεται που.

Η επόμενη εντολή είναι η εντολή ip address IP subnet mask και είναι η εντολή με την οποίαμπορούμε να ορίσουμε την IP και την μάσκα υποδικτύωσης που θα έχει το serial interface.Η IP και το subnet mask που θα βάλουμε εξαρτάται και από την IP που μας έχουν δώσει και το subnetting που έχει γίνει.

Τέλος βλέπουμε τις εντολές clock rate και no shutdown.Η εντολή clock rate ορίζει το clock rate του serial interface και θα πρέπει να χρησιμοποιείται σε όλα τα serial interfaces που είναι DCE και η εντολή no shutdown χρησιμοποιείται για να ενεργοποιήσει το interface.

Ρύθμιση του Fast Ethernet interface

Οι εντολές για το Fast Ethernet δεν διαφέρουν από τις εντολές που είδαμε παραπάνω για να ρυθμίσουμε το serial interface.Η μόνη ουσιαστική διαφορά είναι ότι αυτήν την φορά θα πρέπει από το Global Configuration mode να μπούμε στο fast ethernet interface και αυτό γίνεται με την εντολή interface fastethernet 0/0.

Παράδειγμα:

Router (config)# interface fastethernet 0/0

Router (config-if)# description Logistirio

Router (config-if)# ip address 192.168.100.20 255.255.255.0

Router (config-if)# no shutdown

Δημιουργία μηνύματος Message of the Day

Η δημιουργία μηνυμάτων Message of the Day εμφανίζεται σε όλα τα τερματικά και είναι χρήσιμη για την αποστολή μηνυμάτων προς όλους τους χρήστες.Για παράδειγμα σε περίπτωση που θέλουμε να τους ενημερώσουμε για κάτι.

Router (config)# banner motd # To Internet tha diakopei aurio stis wres 10 me 12 to prwi. #

Router (config)#

Δημιουργία μηνύματος login

Σε περίπτωση που θέλουμε να δημιουργήσουμε ένα μήνυμα στον router που θα εμφανίζεται πριν από το login η εντολή είναι η ακόλουθη:

Router (config)# banner login # Authorized Personnel only! Please enter your username and password. #

Router (config)#

Ορισμός hostname σε μία IP διεύθυνση

Επειδή είναι δύσκολο να θυμόμαστε ποιά IP έχουμε ορίσει και σε ποιόν router είναι ευκολότερο αν θέλουμε να χρησιμοποιήσουμε εντολές όπως telnet και ping για να δούμε για παράδειγμα την συνδεσιμότητα να χρησιμοποιήσουμε τα ονόματα των router.Για να αντιστοιχίσουμε λοιπόν την IP του router σε hostname πληκτρολογούμε την παρακάτω εντολή:

Router (config)# ip host datalibrary 172.16.1.4

Φυσικά όπου datalibrary βάζουμε το hostname που θέλουμε και όπου 172.16.1.4 την IP του router.

Πλέον μπορούμε αντί για το 172.16.1.4 να χρησιμοποιήσουμε το hostname απευθείας.Δηλαδή:

Router# ping datalibrary

Πλέον έχουμε κάνει όλες τις βασικές ρυθμίσεις στον cisco router και το μόνο που μένει είναι να τις σώσουμε στην NVRAM.Η εντολή που θα χρειαστούμε είναι η copy running-config startup-config και μπορούμε να την χρησιμοποιήσουμε ενώ είμαστε στο privilege mode.

Router# copy running-config startup-config

Αυτές είναι όλες οι βασικές εντολές που θα χρειαστούμε για να ρυθμίσουμε έναν cisco router.

For a last few days my Macbook “assumed” a weird hostname: kousik-mac(2) — I don’t know what I did that caused it. Here are three ways to change it (I don’t know if these qualify to be “NIX tricks” ):

1. Click at the Sharing option in System Preferences and then click at Edit. You may change the computer name as well.

2. Use the following commandline-fu:
$ sudo scutil --set HostName your-preferred-hostname

3. Edit the preference file
$ sudo vi /Library/Preferences/SystemConfiguration/preferences.plist
Search for LocalHostname and change the text within the  <string>...</string> just under it. While you’re at it, you may want to change the string under ComputerName (need I say what it does?), as well — this key comes just after the previous one (HostName).

$sudo scutil –set ComputerName “newcompname”
$sudo scutil –set LocalHostName “newhostname”

Reference this article: http://www.ducea.com/2006/08/07/how-to-change-the-hostname-of-a-linux-system/

To change the hostname of a Debian system and make it permanent, you will have to edit this file

/etc/hostname

Enter the new hostname that you wish to change to then run this command:

/etc/init.d/hostname.sh start
Logout and log back in to see if the changes are active

DNS là gì ?

DNS là từ viết tắt trong tiếng Anh của Domain Name System, là Hệ thống phân giải tên được phát minh vào năm 1984 cho Internet, chỉ một hệ thống cho phép thiết lập tương ứng giữa địa chỉ IP và tên miền. Hệ thống tên miền (DNS) là một hệ thống đặt tên theo thứ tự cho máy vi tính, dịch vụ, hoặc bất kỳ nguồn lực tham gia vào Internet. Nó liên kết nhiều thông tin đa dạng với tên miền được gán cho những người tham gia. Quan trọng nhất là, nó chuyển tên miền có ý nghĩa cho con người vào số định danh (nhị phân), liên kết với các trang thiết bị mạng cho các mục đích định vị và địa chỉ hóa các thiết bị khắp thế giới.

Phép tương thường được sử dụng để giải thích hệ thống tên miền là, nó phục vụ như một “Danh bạ điện thoại” để tìm trên Internet bằng cách dịch tên máy chủ máy tính thành địa chỉ IP

Ví dụ, www.example.com dịch thành 208.77.188.166.

Hệ thống tên miền giúp cho nó có thể chỉ định tên miền cho các nhóm người sử dụng Internet trong một cách có ý nghĩa, độc lập với mỗi địa điểm của người sử dụng. Bởi vì điều này, World-Wide Web (WWW) siêu liên kết và trao đổi thông tin trên Internet có thể duy trì ổn định và cố định ngay cả khi định tuyến dòng Internet thay đổi hoặc những người tham gia sử dụng một thiết bị di động. Tên miền internet dễ nhớ hơn các địa chỉ IP như là 208.77.188.166 (IPv4) hoặc 2001: db8: 1f70:: 999: de8: 7648:6 e8 (IPv6).

Mọi người tận dụng lợi thế này khi họ thuật lại có nghĩa các URL và địa chỉ email mà không cần phải biết làm thế nào các máy sẽ thực sự tìm ra chúng.

Hệ thống tên miền phân phối trách nhiệm gán tên miền và lập bản đồ những tên tới địa chỉ IP bằng cách định rõ những máy chủ có thẩm quyền cho mỗi tên miền. Những máy chủ có tên thẩm quyền được phân công chịu trách nhiệm đối với tên miền riêng của họ, và lần lượt có thể chỉ định tên máy chủ khác độc quyền của họ cho các tên miền phụ. Kỹ thuật này đã thực hiện các cơ chế phân phối DNS, chịu đựng lỗi, và giúp tránh sự cần thiết cho một trung tâm đơn lẻ để đăng ký được tư vấn và liên tục cập nhật. Nhìn chung, Hệ thống tên miền cũng lưu trữ các loại thông tin khác, chẳng hạn như danh sách các máy chủ email mà chấp nhận thư điện tử cho một tên miền Internet. Bằng cách cung cấp cho một thế giới rộng lớn, phân phối từ khóa – cơ sở của dịch vụ đổi hướng , Hệ thống tên miền là một thành phần thiết yếu cho các chức năng của Internet. Các định dạng khác như các thẻ RFID, mã số UPC, ký tự Quốc tế trong địa chỉ email và tên máy chủ, và một loạt các định dạng khác có thể có khả năng sử dụng DNS.

2. Chức năng của DNS

Mỗi Website có một tên (là tên miền hay đường dẫn URL:Universal Resource Locator) và một địa chỉ IP. Địa chỉ IP gồm 4 nhóm số cách nhau bằng dấu chấm(Ipv4). Khi mở một trình duyệt Web và nhập tên website, trình duyệt sẽ đến thẳng website mà không cần phải thông qua việc nhập địa chỉ IP của trang web. Quá trình “dịch” tên miền thành địa chỉ IP để cho trình duyệt hiểu và truy cập được vào website là công việc của một DNS server. Các DNS trợ giúp qua lại với nhau để dịch địa chỉ “IP” thành “tên” và ngược lại. Người sử dụng chỉ cần nhớ “tên”, không cần phải nhớ địa chỉ IP (địa chỉ IP là những con số rất khó nhớ).[1]

3. Nguyên tắc làm việc của DNS

-Mỗi nhà cung cấp dịch vụ vận hành và duy trì DNS server riêng của mình, gồm các máy bên trong phần riêng của mỗi nhà cung cấp dịch vụ đó trong Internet. Tức là, nếu một trình duyệt tìm kiếm địa chỉ của một website thì DNS server phân giải tên website này phải là DNS server của chính tổ chức quản lý website đó chứ không phải là của một tổ chức (nhà cung cấp dịch vụ) nào khác.

INTERNIC (Internet Network Information Center) chịu trách nhiệm theo dõi các tên miền và các DNS server tương ứng. INTERNIC là một tổ chức được thành lập bởi NFS (National Science Foundation), AT&T và Network Solution, chịu trách nhiệm đăng ký các tên miền của Internet. INTERNIC chỉ có nhiệm vụ quản lý tất cả các DNS server trên Internet chứ không có nhiệm vụ phân giải tên cho từng địa chỉ.

DNS có khả năng tra vấn các DNS server khác để có được một cái tên đã được phân giải. DNS server của mỗi tên miền thường có hai việc khác biệt. Thứ nhất, chịu trách nhiệm phân giải tên từ các máy bên trong miền về các địa chỉ Internet, cả bên trong lẫn bên ngoài miền nó quản lý. Thứ hai, chúng trả lời các DNS server bên ngoài đang cố gắng phân giải những cái tên bên trong miền nó quản lý. – DNS server có khả năng ghi nhớ lại những tên vừa phân giải. Để dùng cho những yêu cầu phân giải lần sau. Số lượng những tên phân giải được lưu lại tùy thuộc vào quy mô của từng DNS.

4. Cách sử dụng DNS

Do các DNS có tốc độ biên dịch khác nhau, có thể nhanh hoặc có thể chậm, do đó người sử dụng có thể chọn DNS server để sử dụng cho riêng mình. Có các cách chọn lựa cho người sử dụng. Sử dụng DNS mặc định của nhà cung cấp dịch vụ (internet), trường hợp này người sử dụng không cần điền địa chỉ DNS vào network connections trong máy của mình. Sử dụng DNS server khác (miễn phí hoặc trả phí) thì phải điền địa chỉ DNS server vào network connections. Địa chỉ DNS server cũng là 4 nhóm số cách nhau bởi các dấu chấm.

If you have a system with a fresh installed Solaris 10 and it does not have an entry with ‘name server’, there are chances that it’ll set the hostname as ‘unknown’. To change this hostname you need to edit 3 files, follow the following steps:

For the sake of example, say the IP of my system is 192.168.1.32 and I want to set the hostname to ’sol10_sparc’

File 1

Use a text editor like vi to open and edit the following file:

# vi /etc/hosts

By default you’ll find the following line in the above file:

192.168.1.32 unknown #set by DHCP

Simply edit the file to replace ‘unknown’ with your hostname to make it look like as:

192.168.1.32 sol10_sparc #set by DHCP

File 2

Next we need to edit the file called nodename

# vi /etc/nodename

Just insert the hostname ’sol10_sparc’ into this file.

File 3

And now last, find out the name of your ethernet card with the ‘ifconfig -a’ command. Say my ethernet card is called ‘rge0′. I’ll create and edit the following file:

# vi /etc/hostname.rge0

Insert your new hostname ’sol10_sparc’ in this file, save and exit.

Restart your machine:

# init 6

That’s it, after your machine restarts, check the hostname:

# hostname

Done, enjoy

Two options:

/etc/hostname

Can be edited with gedit for instance, not sure if you need root permissions.

If you’re only interested in changing the hostname that is sent, or rahter seen by, the network, you can change the dhcp settings.

In /etc/dhcp3/dhclient.conf you can see right after the initial comments this:

send host-name "<hostname>";

You edit it to something like

#send host-name "<hostname>";
send host-name "m4m";

You’re good to go.

I ran into a problem when I started to host WCF services on Server 2008 in that I kept getting the netbios name of the server instead of the service website in the service metadata and WSDL. 

I created a website with a unique IP address on my Windows 2008 server with the address of http://IISHostedServices.maltercorp.com and the virtual website to host the service is MaltercorpService.  When I browsed on my service, I got the following metadata page:

Bad Metadata

As you can see in the address bar, the correct ip address is used, but the complete URL of the website does not appear.  A little further down you can see that the metadata page thinks I am pointing to mmant2 which is the netbios name of the server.  It’s address is 10.1.2.0.

The fix was to edit the binding of the website and to use the same name I used in DNS to point to the site.  I want to point out that there are a number of blog entries out there that explain how to fix this problem but they are recommending the use of the IIS utility tool adsutil.vbs, killing the w3wp.exe process and several other steps.

I am adding my solution because it differs in that the IIS UI was used to change the binding.  Personally I found it easier to use the UI as shown in the screenshot below.  I did not have to do anything additional after adding a hostname:

Edit Binding in IIS UI

After adding the hostname, which is the same address I configured DNS to point to, I simply restarted the site and when I browsed on the service, this time the correct name of the website appeared on the metadata page.  Also notice that in the address bar, instead of the ip address appearing, the actual URL for the web site appears.

Good Metadata

Just as an FYI, in a related post, I am writing a series of articles on a practical WCF architecture. The first post is here.