Wednesday, September 29, 2010

Gnome Mplayer

Gnome MPlayer simply rocks, the amount of control it gives us is simply amazing :-D
Press C for Compact mode, and use the arrow keys to move forward and reverse cool :-D  I am loving it :-D

Sunday, September 26, 2010

Four Stages of DHCP capture by Wireshark

Today I thought let me investigate a little bit about the four process which goes into the DHCP request.

First is the DHCP Discovery, where the blind client sends out Broadcast.

Next packet we can see there is an ICMP echo request for an IP from the vmware to see if any client is using it.

It also tries to see if there is an ARP entry for it in the next two packets.  No reply comes back.

Now the DHCP server offers the client the IP from which no ICMP reply or ARP reply came.

Now we see that the client requests the server that it will use the IP address provided to it from the DHCP server.

The last step is where the DHCP server acknowledges the request.

After this if you see there is a Gracious ARP :-D

If there are any mistake do let me know.

How to stop DHCP on a specific vmnet subnet ?

Here we will see how we can stop the DHCP service on VMNET3 subnet of VMWARE.  It took me around 5 hrs to search this, while the answer was right beneath my nose :-D

bala@bala-laptop:~$ sudo /usr/lib/vmware/     stop    3
[sudo] password for bala:
   DHCP server on /dev/vmnet3                                          done
   NAT service on /dev/vmnet3                                           done
   Host-only networking on /dev/vmnet3                            done
bala@bala-laptop:~$ sudo /usr/lib/vmware/     start    3
   Host-only networking on /dev/vmnet3 (background)      done
   DHCP server on /dev/vmnet3                                          done
   NAT service on /dev/vmnet3                                            done

All we need to do is to follow the first command with the word DHCP.

bala@bala-laptop:~$ sudo /usr/lib/vmware/    stop    3   dhcp
   DHCP server on /dev/vmnet3                                          done


Monday, September 13, 2010