Category: Information

Categories
Information

Got a Computer/Tech Question(s)?

To my readers:

Please send me some ideas of what you would like answered?

(This ought to be fun!)

– Andrew
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Categories
Information Reviews

Switch from Blogger to WordPress

Well after making the connection from Blogger to FaceBook, I started to look at the Core of the platform, and decided to switch to WordPress as my blogging platform. If you want to hear more details, please let me know.

Update – 09-Dec-07 @ 13:14

Another thing that just came across is the ability to use MS Word 2007 to blog to WordPress!

Really easy!

Note – Need to say the Local Block page as Native MS 2007 format (.docx)

– Andrew
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Categories
Information Networking

OpenDNS and Comcast DHCP/DNS issues

Couple of weeks ago, I got knocked off the internet, and it took me awhile to figure out what when wrong.

Background –
I’m working with a new client and their application requires a high speed network to do what they want to do. So I finally had an excuse to purchase 1GB network equipment upgrade: a Network switch and a Network NIC.

I installed the switch and NIC without issue, and proceeded to “clean out” my Server.

I literally pulled all cables and took the machine out to the garage and used an air compressor to dust the beast out.

After the major dusting, in which clouds of dust escaped from the open garage, I also removed several unused PCI cards, and finally put things back together, and got the internal network running, but could not connect to the internet.

Issues –
I could connect to all my internal machines, but I could not connect from any machine out via Name.

Oddly, I could “ping” outside servers by IP address, but could not by Name, even when directly connected to the cable modem.

A couple of times, after hard resetting the cable modem and firewall/router, there would be access for a while, or be deathly slow.

Resolution –
I had to shut down shutdown the network, except for the main server.

Opened DNS manager and cleared any and all DNS caches, along with stopping and starting the server, and a reboot or two for good measure.

Then directly connected the main server to the “cable modem” via wired ethernet.

I changed the Server’s static IP address to be on the same sub-net as the cable modem (192.168.100.1).

Connect to OpenDNS, and delete the old IP information, and setup new IP information.

Reconfig the server back to it’s original IP range, connect firewall/router to modem, and reconnect to OpenDNS.

Finds –

I went through all my settings, machine by machine, flushed caches, renewed IP, reset WinSock, etc.

  • Comcast has 1 hour DHCP address renewal
    • Seems that when I had my server down for cleaning, it missed a DHCP “conversation” and my external IP changed.
  • OpenDNS
    • Was using my Old IP address and for some reason would not resolve IPs to Name.

Lessons Learned –
Since I originally ran into this issue, it has happen one more time, but I immediately connected the server to the cable modem, reestablished OpenDNS connectivity, and moved ethernet cables back. (Estimated time: 10 minutes vs. Hours of Troubleshooting)

I have also downloaded and installed the OpenDNS agent, and is running all the time.

– Andrew
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Categories
Information Reference

OpenDNS and GoogleDNS

This is a rehash of a Facebook conversation from earlier today….

Originally, I posted a link to “Google Public DNS offers speed, few features” in which I made the comments that this could get interesting, and ended up doing a quick DNS description:

“DNS is a foundation level services that helps run the internet. Every device on the internet has a unique IP number that usually takes the form of [74.125.53.100]. Since humans are not that good with remembering numbers, we add names, such as google.com… What DNS does is translate backwards and forwards of IP Numbers [74.125.53.100] to Human Name [google.com]. Think of DNS as a Yellow & White pages phonebook for the internet.”

“When one connects to the internet from home or at work, that device uses DNS to find “stuff” for you. If you have an ISP (Comcast, Verizon, etc.) they give you their DNS Server addresses, which is fine for most folks, but with a little bit of techo-tink, one can access Open Public DNS servers that are usually faster then an ISPs, so your access is a bit faster.”

“Setting up your account is primary, but once done, the basics are that you need to access your router/firewall and change the DNS servers that they are “pointed to”. Some routers offer away to add more the two (2) entries. If this is possible, make your Open Public DNS servers the Top priority in the list.”

As a reference:

OpenDNS
208.67.222.222
208.67.220.220

Google Public DNS
8.8.8.8
8.8.4.4

– Andrew
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Categories
Information Reference Software

Windows Boot Sequence

  1. Turn on your computer;
  2. The Computer initiates a POST (Power On Self Test) for devices that have a BIOS (Basic Input/Output System);
    • Test the memory & various Subsystems
      • Examples: AGP and Network cards
  3. BIOS then attempts to find the MBR (Master Boot Record)
    • A 512-byte sector (LBA 0 or HD0)
  4. If successful, the Windows OS takes Control, and looks for NTLDR(Boot Loader for Windows NT based OSes)
    1. In Vista and Server 2008, this has been replaced with:
    2. NTLDRallows:
      1. Memory Addressing
      2. Initiates the File System
      3. Reads boot.ini
    3. NTLDRhas to be at the ROOT of an active partition to detect:
      1. NTDETECT.COM
      2. BOOT.INI
      3. BOOTSECT.DOS (needed for multi-OS installs)
      4. NTBOOTDD.SYS(need for SCSI adapters)
        • Only used if:
          • Boot Drive is SCSI;
          • Not using real-mode INT 0x13;
        • Then a copy of the SCSI miniport driver is loaded for Windows to run
      5. Troubleshooting:
  5. If XP is selected in the Boot Menu, NTLDRruns:
    1. NTDETECT.COM
      • Gathers basic information from hardware BIOs
    2. BOOT.INI
    3. BOOTSECT.DOS
    4. The systems starts in 16-bit real mode, and then moves into 32-bit protected mode
    5. It is possible to select F8 for Additional Boot Modes (Safe Mode, Last Known Good Configuration, etc.)
  6. NTLDR then loads NTOSKRNL.EXE and HAL.DLL
    1. Located at: %SystemRoot%System32
    2. Additional files/locations loaded:
      1. kdcom.dll (Kernel Debugger HW)
      2. bootvid.dll (Windows Logo & Side-Scrolling bar)
  7. NTLDRreads the Registry for the following information:
    1. Hardware Profile
    2. Authorized Device Drivers
    3. And needs to be in the Exact Order
  8. “Session Manager” is then started
    1. Smss.exe starts Autochk
      1. Mounts all drives
      2. Checks drives for a Clean shutdown state
    2. Starts win32k.sys for the Graphical User Interface (GUI) interface
    3. Starts csrss.exe (Client/Server Runtime Subsystem)
      1. User-Mode Applications
    4. Creates Virtual Memory/Paging file
      1. HKLMSYSTEMCurrentControlSetControlSession ManagerMemory Management
  9. NTOSKRNL.EXE takes control and starts WINLOGON.EXE which in turn starts LSASS.EXE
    1. LSASS.EXE (Local Security Authority Subsystem Service) provides the Logon screen
– Andrew
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