I beleive you'll find remnants of a time whence such information was more
remotely accessible.
$ more /etc/inetd.conf
...
# Finger, systat and netstat give out user information which may be
# valuable to potential "system crackers." Many sites choose to disable
# some or all of these services to improve security.
# Try "telnet localhost systat" and "telnet localhost netstat" to see that
# information yourself!
#
...
Thanks,
Ron DuFresne
On Mon, 9 Oct 2000, Jason Axley wrote:
> The system may support what is called an "ICMP Netmask" request where you
> can send a specific ICMP packet to the host and it will respond with its
> netmask in another ICMP packet. You can do the same to find the remote
> time on the machine ("ICMP Timestamp" request) too.
>
> A program called SING (Send ICMP Nasty Garbage) is available at
> http://sourceforge.net/projects/sing/ that can send all kinds of ICMP
> messages and may be able to retrieve this information from the
> host.
>
> -Jason
>
> On Mon, 9 Oct 2000, Hafida Fouta wrote:
>
> > Date: Mon, 9 Oct 2000 14:52:55 +0000 (GMT)
> > From: Hafida Fouta <[EMAIL PROTECTED]>
> > To: [EMAIL PROTECTED]
> > Cc: [EMAIL PROTECTED]
> > Subject: Re: Subnet mask
> >
> >
> > Yes, What I wanted to say is that I know the IP address of a host. How
> > can I communicate with this host to get its subnet mask. I know that it is
> > using row sockets and ICMP packets but I don't know how?
> >
> >
> >
> > On Mon, 9 Oct 2000 [EMAIL PROTECTED] wrote:
> >
> > >
> > > #I have the IP address of a host and I want to get its subnet mask
> > > #can any one tell me how I can do this?
> > >
> > > I got the following information off of the Cisco website a while ago (I
> > > think). The IP address alone no longer gives you the netmask because of
> > > CIDR. Any IP address can have a number of different netmasks depending on
> > > how the network engineers are divvying up the network.
> > >
> > > Regards,
> > > Jeffery Gieser
> > >
> > >
> > > Netmasks and Netblock Sizes
> > >
> > > Netblock Sizes, Netmasks, and Bit-sized Networks
> > > The following table shows the relationship between IP network's block
> > > sizes, classful interpretation, netmasks, "supernets" [bit-length], "cisco
> > > wild bits" and the actual bit-sizes of the networks.
> > >
> > >
> > > An IP address on its own does not communicate what size network block to
> > > which it belongs. A netmask associated with an IP address describes
> > > "masked" portions [the left-most bits 'blocked out' by the ones in the
> > > netmask] of an IP address. These masked portions create the "network part"
> > > of the address, commonly called the "prefix".
> > >
> > > Block Size
> > > The block size tells you how many addresses are within the network. The
> > > "bottom" [all-zero] is reserved to refer to the network itself and "top"
> > > [all-ones] is reserved as the broadcast address, so these are unusable.
> > > therefore, any given netblock has two less usable addresses that the
> > > literal block size.
> > >
> > >
> > > Eg, a network 10.0.0.64 with a block size of four has only two usable
> > > addresses, 10.0.0.65 and 10.0.0.66.
> > >
> > > Netmask
> > > The netmask indicates the final (or final two) octets of what should be
> > > masked against the address to configure equipment or define routes with the
> > > apropriately-sized network. All leading [leftmost] octets in a netmask are
> > > ones.
> > >
> > >
> > > Eg, a network 10.0.16.0 with a netmask of 252.0 would result in a network
> > > netmask pair of 10.0.16.0 255.255.252.0, while the previous example from
> > > block size would result in 10.0.0.64 255.255.255.252.
> > > Cisco "Wild Bits"
> > > The cisco wild bits indicate the apropos value for the final (or final two)
> > > octets of what is needed when creating a Cisco router's access list for a
> > > certain network size. It is one less than the block size, merely because
> > > given the network number [the "zero" or "bottom" of the network], the "wild
> > > bits" define all the remaining possible values within the network.
> > >
> > > "Supernet"
> > > The supernet notation indicates the literal bitsize of a network.
> > > "Supernet" is actually a misnomer, stemming from the perceived need to
> > > differentiate prefixes longer than 24-bits [subnets of "Class C" blocks]
> > > from those shorter than 24-bits in traditional "Class C space" (eg, the
> > > 207.* network), calling ther latter "supernets". The number actually
> > > represents the "prefix length" - what part of an address is the
> > > network-part.
> > >
> > >
> > > Given that IPv4 addresses are 32-bits long, this is the most common and
> > > easy way of describing a network. A network of one device (a host route) is
> > > defined as easily as a network of two hundred fifty-six devices:
> > > 10.0.99.99/32 is a host and 10.0.98.0/24 is a "C-sized block".
> > >
> > >
> > > This notation is the UltraNet standard for describing network sizes.
> > >
> > > Raw Bits
> > > The raw bits define the bits "within" the network. These are the inverse of
> > > the supernet notation, and are a bitwise representation of the blocksize.
> > > Lastly, this is the exponent for "2" when describing the network
> > > mathematically.
> > >
> > > Classful
> > > The classful row merely gives a "backwards compatible" reference. All
> > > classful interpretations [Class A, B, C, D and E networks] of IPv4 space
> > > are archaic. This row is provided to give a reference point when speaking
> > > to customers that do not yet have a firm grasp of "supernet" notation.
> > >
> > > Reference Table
> > > Netmasks and Wild Bits refer to the RIGHTMOST octets.
> > >
> > >
> > > block size 1 2 4 8 16 32 64 128 256
> > > netmask 255 254 252 248 240 224 192 128 0
> > > cisco wild bits 0 1 3 7 15 31 63 127 255
> > > supernet /32 /31 /30 /29 /28 /27 /26 /25 /24
> > > raw bits 0 1 2 3 4 5 6 7 8
> > > Classful |------ Subnets of Class C addresses ------|
> > >
> > >
> > > block size 512 1024 2048 4096 8192 16384 32768
> > > netmask 254.0 252.0 248.0 240.0 224.0 192.0
> > > 128.0
> > > cisco wild bits 1.255 3.255 7.255 15.255 31.255
> > > 63.255 127.255
> > > supernet /23 /22 /21 /20 /19 /18 /17
> > > raw bits 9 10 11 12 13 14 15
> > >
> > > Classful |--------- Subnets of Class B addresses --------|
> > >
> > >
> > > block size 65536
> > > netmask 0.0
> > > cisco wild bits 255.255
> > > supernet /16
> > > raw bits 16
> > > Classful Class B
> > >
> > >
> >
> > -
> > [To unsubscribe, send mail to [EMAIL PROTECTED] with
> > "unsubscribe firewalls" in the body of the message.]
> >
>
> --
>
> AT&T Wireless Services
> IT Security
> UNIX Security Operations Specialist
>
> -
> [To unsubscribe, send mail to [EMAIL PROTECTED] with
> "unsubscribe firewalls" in the body of the message.]
>
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