PIX public/24 ip static mapping means 256 times interfaces static maps?

Discussion in 'Cisco' started by Nieuws Xs4all, May 26, 2005.

  1. Hi there,

    have a pix (525, 6.3.3) securing a public class-C network /24

    Want to get data in and out only based on ACL.
    So want to have this /24 network staticly mapped with no network
    translation whatsoever

    Something like
    static (inside,outside) zz.yy.xx.0 zz.yy.xx.0 netmask 255.255.255.0 0 0

    This is accepted, but seems of no use ( perhaps getting from a higher
    security interface to a lower).
    However a nat 0 rule works for that also

    However when I do

    static (inside,outside) zz.yy.xx.1 zz.yy.xx.1 netmask 255.255.255.255 0 0
    static (inside,outside) zz.yy.xx.2 zz.yy.xx.2 netmask 255.255.255.255 0 0
    static (inside,outside) zz.yy.xx.3 zz.yy.xx.3 netmask 255.255.255.255 0 0

    etc, etc, it does work. I can get from a lower security device to a higher
    security device.

    Since I also got a lot of ( virtual) interfaces, this mean 256 times all
    the interfaces, is a lot of rules.

    I guess i miss something obvious then, don't I?

    Thanks for your time

    Jan-Willem Michels





    I have tried outgoing a nat null rule and with incomming static rules
     
    Nieuws Xs4all, May 26, 2005
    #1
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  2. :have a pix (525, 6.3.3) securing a public class-C network /24

    There are some security issues in 6.3(3) [and some important bugs]
    so you may wish to consider updating to 6.3(4)110 . Search cisco.com
    for PIX Security Advisories for more details.


    :Want to get data in and out only based on ACL.
    :So want to have this /24 network staticly mapped with no network
    :translation whatsoever

    :Something like
    :static (inside,outside) zz.yy.xx.0 zz.yy.xx.0 netmask 255.255.255.0 0 0

    That should work.

    For your purposes, you could use nat 0 access-list


    Note: when you use a netmask of other than 255.255.255.255 on
    a static, then the PIX will consider the highest and lowest address
    on the inside to be reserved for broadcast addresses. There is a
    work-around but it sometimes has problems.
     
    Walter Roberson, May 26, 2005
    #2
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  3. Nieuws Xs4all

    Jan-Willem Guest

    :have a pix (525, 6.3.3) securing a public class-C network /24
    Thanks. I guess when I go up i will use 7.0.1.
    Has a lot of nice features, like being able to send data back the same
    interface it came on.
    Yes. But the trouble is, it doesn't work
    Supose I have a nat 0 rule.
    And have static (inside,outside) zz.yy.xx.0 zz.yy.xx.0 netmask 255.255.255.0
    0 0

    If I do clear xlate, I can't acces the network inside from outside
    My licences then are also very low ( I have an unlimited license).
    If I do anything to any netwerk from inside to outside, then my license goes
    up one, and from that moment on I can get in from outside ( until I reload
    or clear xlate)
    If I wouldn't have the static (inside,outside) zz.yy.xx.0 zz.yy.xx.0 netmask
    255.255.255.0 0 then in that case I can't get in of course

    However if do static (inside,outside) zz.yy.xx.2 zz.yy.xx.2 netmask
    255.255.255.255 0 ( So only one ipadress, with single netmask)
    Then my license goes up with one at once. And I can always get contact from
    inside to outside. Even when I have done clear xlate

    So static (inside,outside) zz.yy.xx.0 zz.yy.xx.0 netmask 255.255.255.0 0
    wil give me the right to get in, but doesn't create the corresponding xlate
    entries
    Not al my equipment sends data out once in a while, so a can't get to these
    adresses.
    Having 256 static entries multiple the interfaces looks a bit stupid.
     
    Jan-Willem, May 26, 2005
    #3
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