• VmWare ESXi 5.1 driver issue with Dell servers .

    VmWare ESXi 5.1 driver issue with Dell servers .

     

    Today i had to setup VmWare ESXi on a new server ( Dell PowerEdge R320 ) .
    Firstly, I downloaded latest exsi 5.1 and tried to install. But it was throwing network driver errors.

    After some googling, I found a “Repaired vmware exsi 5.1 iso ” from Dell support .

    If you are facing the same issue then please download the dell .iso from the following location

     Download from here :

    Dell_Customized_RecoveryCD_A00.iso

    Sometimes you may face issues to download from this location , then you may try ” wget” in linux .

    wget http://downloads-us.dell.com/FOLDER00876460M/1/VMware-VMvisor-Installer-5.1.0-799733.x86_64-Dell_Customized_RecoveryCD_A00.iso

    Thats it !!  Enjoy new 5.1 ESXi !!!! 

     

  • Network packet monitoring using tcpdump and WireShark

    Some times we need to monitor our network traffic closely to find out the misbehavior of the server.
    I found a combination of two excellent tools ( tcpdump and wireshark )  to meet my requirements.

    Tcpdump (http://www.tcpdump.org ) : –

    tcpdump is a well known packet capturing tool used in unix machines.  Also its freely available with most of the distributions.

    How to  use the tcpdump commands

    tcpdump -i <interface> -s <packet snapshot length >  -w <some-file>

    1) Capture packets and give the standard output to shell.

    tcpdump  -i eth0 -s 65535

    c – count ( number of packets )
    i – specify the interface
    s – packet snapshot length (def: 65535)
    2) Capture packets and write the result in to a file ( file.cap ) using ” -w ” option

    tcpdump -c 2 -i eth0  -w file.cap

    3) Read the captuared file , file.cap

    tcpdump -tttt -r file.cap

    4) Capture the packets coming through a specific port

    tcpdump -i eth0  -c 100 port 22

    5) Capture the packets from a specific destination IP

    tcpdump -i eth0 port 80 and dst 119.168.20.112

    WireShark (www.wireshark.org):

    Wireshark is the world’s foremost network protocol analyzer. It lets you capture and interactively browse the traffic running on a computer network.

    How to diagnosis the captuared packets using  WireShark

    1) Download and  install this software to your local machine windows or linux .
    2) copy / download the captuared file ” file.cap ” to your local machine.
    3) Open the file in wireshark


     

    Just like the above pictures , its a GUI . You can diagnosis the packets very easily.

  • Good bye 2.6

    Another proud moment for linux lovers , kernel 3 released !!!

    Linux successfullly completed 2 decades and entering to the 3rd decade with 3rd generation kernel.




    Refer the official details from : Linus Torvalds  and  Kernel Org

    You can view the 20 years story here : The Story

    Good bye 2.6  !!!!!!

  • Useful websites for System Admins

    I  use the following url’s frequently as part of my system administration job.

    Today i decided to keep these url’s  in a single page for quick reference.

    To find your ISP ip
    http://www.whatismyip.com/

    DNS Lookup
    http://network-tools.com/
    http://www.mxtoolbox.com/DNSLookup.aspx
    http://www.dnswatch.info/
    http://www.dnsstuff.com/

    MX lookup
    http://www.mxtoolbox.com/

    Spam lookup
    http://www.spamhaus.org/lookup.lasso
    whatismyipaddress.com/blacklist-check
    http://www.mxtoolbox.com/blacklists.aspx

    SSL Verification
    https://www.ssllabs.com/ssltest/
    http://www.digicert.com/help/
    https://knowledge.verisign.com/support/ssl-certificates-support/index?page=content&id=AR1130&actp=LIST&viewlocale=en_U

    Vulnerable file check
    http://unmaskparasites.com/

    Hope this will be helpful for  you also 🙂