Subnetting Question

Discussion in 'Computer Support' started by meerkat, Jan 25, 2008.

  1. meerkat

    meerkat Guest

    <> wrote in message
    news:...
    >I just received IP information for a new Internet connection and they
    > did not include the Subnet Mask. How can I figure this address? The
    > IP is 63.253.x.x
    >

    Try...
    255.255.255.0
     
    meerkat, Jan 25, 2008
    #1
    1. Advertising

  2. meerkat

    Guest

    I just received IP information for a new Internet connection and they
    did not include the Subnet Mask. How can I figure this address? The
    IP is 63.253.x.x
     
    , Jan 25, 2008
    #2
    1. Advertising

  3. meerkat

    John Doe Guest

    Hey, thanks for the quick response!
    I'm having to pre-configure a router for an office in another city.
    Is there an exact equation that anyone knows of?
    Honestly, I'm afraid to ask the ISP a stupid question but I might just
    have to ask them why they didn't supply the Subnet Mask.
     
    John Doe, Jan 25, 2008
    #3
  4. meerkat

    richard Guest

    On Fri, 25 Jan 2008 10:21:13 -0800 (PST), John Doe
    <> wrote:

    >Hey, thanks for the quick response!
    >I'm having to pre-configure a router for an office in another city.
    >Is there an exact equation that anyone knows of?
    >Honestly, I'm afraid to ask the ISP a stupid question but I might just
    >have to ask them why they didn't supply the Subnet Mask.


    Maybe it's not needed.
     
    richard, Jan 25, 2008
    #4
  5. meerkat

    Gaius Baltar Guest

    On Fri, 25 Jan 2008 10:04:46 -0800 (PST),
    wrote:

    >I just received IP information for a new Internet connection and they
    >did not include the Subnet Mask. How can I figure this address? The
    >IP is 63.253.x.x


    255.255.0.0 covers all the addresses in the 63.253.0.0 network

    gb
     
    Gaius Baltar, Jan 25, 2008
    #5
  6. meerkat

    why? Guest

    On Fri, 25 Jan 2008 10:04:46 -0800 (PST),
    wrote:

    >I just received IP information for a new Internet connection and they
    >did not include the Subnet Mask. How can I figure this address? The


    ..x.x is fairly invalid in most systems.

    >IP is 63.253.x.x


    Don't ask, tell them they forgot to supply that information.

    www.google.com for - subnet calculator

    Depends on if you mean exactly 1 address or a small range.

    At worst case 255.255.0.0 for
    63.253.0.1 - 63.253.255.254
    and how much of that the ISP handed out to other users.

    Me
     
    why?, Jan 26, 2008
    #6
  7. meerkat

    Phat Sam Guest

    On Fri, 25 Jan 2008 10:21:13 -0800 (PST), John Doe
    <> wrote:

    >Hey, thanks for the quick response!
    >I'm having to pre-configure a router for an office in another city.
    >Is there an exact equation that anyone knows of?
    >Honestly, I'm afraid to ask the ISP a stupid question but I might just
    >have to ask them why they didn't supply the Subnet Mask.


    The MASK determines what computers are in your "local" network.
    Determining the MASK is supposed to be done according to the "class"
    of network your on. Some networks allow for configurations of 256 IP
    addresses, some allow for 65536, and others in between. You can
    create some rather freaky combinations, as the subnet mask is actually
    bit-masked in reality. Eg. suppose you specify:

    255.255.255.250

    Then the only computers that'd be local to yours would be those whose
    IP address is the same as yours on the first 3 sections, with the 4th
    section being either 0,1,4, or 5. This method would allow for in
    theory 4 computers on the local network.... Thus if you did

    255.255.255.0 All would be well as long as any of your ISP's has the
    same numbers for the first 3 parts of the IP address.... If not, then
    most ISP's use a subnet mask of 255.255.0.0 Which allows for a range
    of 65536 IP addresses. Thinking about it an ISP with only 256 IP
    addresses would seem rather limited, but your ISP could be a small
    Dial-up with their own equipment (Extremely rare these days as most
    ISP's lease their dial-up lines from other companies....)
     
    Phat Sam, Jan 27, 2008
    #7
  8. meerkat

    why? Guest

    On Sun, 27 Jan 2008 17:20:12 -0600, Phat Sam wrote:

    >On Fri, 25 Jan 2008 10:21:13 -0800 (PST), John Doe
    ><> wrote:
    >
    >>Hey, thanks for the quick response!
    >>I'm having to pre-configure a router for an office in another city.
    >>Is there an exact equation that anyone knows of?
    >>Honestly, I'm afraid to ask the ISP a stupid question but I might just
    >>have to ask them why they didn't supply the Subnet Mask.

    >
    >The MASK determines what computers are in your "local" network.
    >Determining the MASK is supposed to be done according to the "class"


    Except where just about everybody uses CIDR. Haven't used "class" to
    subnet anything for a long time.

    <snip>

    >create some rather freaky combinations, as the subnet mask is actually
    >bit-masked in reality. Eg. suppose you specify:
    >
    >255.255.255.250


    250 is freaky, sensible examples and a URL to a subnet tutorial would be
    more useful, better to use .248 or .252.

    250 isn't contiguous bits, 11111010 and that's mentioned in the RFC as
    not illegal however real life / pratical support and the messy
    addressing means it's not used in and to be avoided.

    >Then the only computers that'd be local to yours would be those whose
    >IP address is the same as yours on the first 3 sections, with the 4th
    >section being either 0,1,4, or 5. This method would allow for in


    0, 1, 4 and 5 is also odd, from your example.

    If you are going to try and explain something about subnetting avoid the
    freaky examples.

    >theory 4 computers on the local network.... Thus if you did


    Why use section in place of the common usage octet?

    <snip>

    Me
     
    why?, Jan 28, 2008
    #8
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. $teve.H

    Question about subnetting on MS Exams

    $teve.H, Nov 10, 2005, in forum: Microsoft Certification
    Replies:
    7
    Views:
    899
    msnews.microsoft.com
    Jan 11, 2006
  2. TeamGracie

    PIX subnetting question

    TeamGracie, Jan 12, 2005, in forum: Cisco
    Replies:
    2
    Views:
    703
    Walter Roberson
    Jan 12, 2005
  3. myrt webb

    Subnetting Question

    myrt webb, Oct 10, 2003, in forum: MCSE
    Replies:
    3
    Views:
    714
    Darko Gavrilovic
    Oct 12, 2003
  4. Kendal Emery
    Replies:
    1
    Views:
    478
    chris
    Nov 21, 2003
  5. M D
    Replies:
    10
    Views:
    1,991
Loading...

Share This Page