Technology

VMWare on Ubuntu

Quick post (more to come later on) on how to install/configure VMWare Server on Ubuntu

1) Install Ubuntu in “server” config
2) Install X-Windows on Ubuntu by using
“sudo apt-get install ubuntu-desktop”
3) install smbmount/mount to access windows shares
“sudo apt-get install smbfs”
NOTE : To map a windows share.. try the following
“sudo mount -t smbfs -o username=WINDOWS_USERNAME,password=WINDOWS_PASSWORD //WINDOWS_SERVER_NAME/c$ /tmp/FOLDER_TO_MOUNT”
4) Install make by
“sudo apt-get install make”
5) To install a smp capable kernel,
a.Search for smp kernel images by using
“sudo apt-cache search smp”
b. Install the appropriate smp kernel from the list. In my case, it was
“sudo apt-get install linux-amd64-k8-smp”
6) Install 3.4 version of GCC so that VMWare can compile the kernel modules
a. sudo apt-get install build-essential
b. Install the kernerl headers for your kernel. To do this, first get the Kernel version by
sudo uname -r
I got “2.6.12-10-amd64-k8-smp”
then get the kernel headers by
sudo apt-get install linux-headers-‘kernel version’, in my case, it would be
sudo apt-get install linux-headers-2.6.12-10-amd64-k8-smp
c. Install 3.4 version of GCC by
sudo apt-get install gcc-3.4
d. Install the right g++ version by
sudo apt-get install g++-3.4
7) Install xinetd
“sudo apt-get install xinetd“

May 9, 2006 by Linux Technology Uncategorized 0

IP Address confusion and DHCP

Ran into a good case of Network troubleshooting today. We use the private 192.168.0.0/16 address range at work. All of a sudden, we had users calling us from a particular floor stating that they cannot access network resources. Here’s how the team solved the issue

1) Physical connectivity – Is the cable plugged into the workstation? Is there a green light on the NIC?
2) DNS Lookup – Open a command prompt and do a look up on a server in the network. In this case, one of our file servers. Users say that they are getting a “server inaccessible” error. Hmm.. Alright, so we have physical connectivity, but don’t have DNS resolution. Since the rest of the user population didn’t have any DNS resolution issues, the team dug deeper
3) IP Address Details – Open a command prompt and type in “ipconfig”. This showed that the affected users were getting a “172.16.0.x” address. This range does not exist in our user network segment. So looks like we have users getting an unqualified network. Since all users are configured to get their IP addresses through DHCP, the culprit might be DHCP.
4) DHCP Server : The Issue – Open a command prompt and type in “ipconfig /all”. This showed the following

Aha.. looks like there is a rouge DHCP server in our network. The team checked the LAN room on the floor and found the culprit server. Looks like the server was installed in it’s default state where it acted as a DHCP server.

Lesson learnt : DHCP broadcasts sent by the client are addressed by servers in the same broadcast (Layer 2) domain before being routed to other DHCP servers (IP Helper Addresses).

April 4, 2006 by Networking Technology Uncategorized Windows 0

Windows : Explore running processes

One of the Windows server at work started running high on CPU for the last few days.. On checking the task manager, I could only see that “services.exe” was using ~30% of CPU. services.exe is part of the core Windows operating system and manages the starting and stopping of the services. To further investigate, what process was using the CPU, I lauched Sysinternals Process Explorer and voila!!, here’s what I see

Looks like the CPU utilization of the services that the services.exe starts show up under it. There are a bunch of other cool utilities at SysInternals that any Windows admin would find useful.

April 4, 2006 by Technology Uncategorized Windows 0

Party time..

I think it is high time I started using Flickr to post my pictures. I take a ton of pictures (yes, I am one of those crazy guys, that carry a camera on them ALL the time) and haven’t found a way to share them with friends and family without maxing out the traffic on my hosted site. I have been looking at all the photo sharing, social tagging sites such as flickr, fotki, hello for quite some time, but never got around to creating an account and using them. I don’t like sites that require you to register just to look at pictures (kodak!!). We have too many accounts as it is, without having to register on a site just to look at some photos.

Long post short :).. Here is the first attempt to start logging my pictures online. The link to my pictures on flickr is
http://www.flickr.com/photos/kudithipudi/sets/72057594092170857/

P.S: If anyone wants me to delete their photos, pls shoot me an E-mail at vinay at kudithipudi dot org. Thx.

March 26, 2006 by Fun Technology Uncategorized Web 0

Another day.. another tech term

IDF – Intermediate Distribution Frame – Otherwise known as the wiring closet in floors or buildings that in turn connect to the core network closet

MDF – Main Distribution Frame – In layman terms, the core network/telecom cabinet/closet in a facility.

March 9, 2006 by Technology Uncategorized 0

Updating NFS Share permissions..

Wanted to add this for my future reference. To update the permissions on a NFS (Network File System) share, you need to edit the “/etc/exports” file and then run “/usr/sbin/exportfs -a” to update the share permissions.

Syntax of /etc/exports looks like
/dir/to/export host1.mydomain.com(ro,root_squash)

UPDATE : Looks like the NFS daemon caches DNS lookups when authenticating a client. Am not sure if this is only in older versions. After we updated the exports file, the server still kep erroring out with a “unresolvable reverse lookup” error. I finally had to restart the daemon to make it check on the DNS records for the accessing client.

March 6, 2006 by Linux Technology Uncategorized 0

What is NPA NXX ?

I am in the middle of ordering some data circuits for our new office and the vendor asks me for the address of the building where the circuits are going to be terminated. I give it to them and they come back with “what is the NPA NXX??” of the location. Now, I should admit that I haven’t been provisioning hardcode data circuits, but have ordered a bunch of T1s and DS3s during my career. I thought this was come kind of technical spec and swallowing my pride, asked the vendor what NPA NXX means.. and the answer..

“there are no dumb questions 🙂
the first six digits of a phone number“

Looking up on the web, gave me this information

NPA = (Numbering Plan Area code) The area code of a telephone number in the NPA system. The first NPA codes used 0 or 1 as the center digit, such as 201, 212, 301, 312, etc., designated as “N0/1X.” After July 1, 1995, all digits 0 through 9 are valid as the center digit, designated as “NXX.”

All I can say is “live and learn” :).

March 3, 2006 by Technology Uncategorized