[LINK] IPv4 host density measured by ping

Robin Whittle rw at firstpr.com.au
Thu Mar 1 11:22:35 AEDT 2007


Howard Lowndes wrote:

> I think your figures are likely to be grossly flawed based on many
> connections being via DSL modems, almost all of which are by default
> configured to not respond to pings.

Can anyone comment on this?

I tried pinging the full range of three /24 prefixes which I know to be
populated by ADSL services:

  150.101.162.0/24   Internode           89 acks

    ppp162-0.static.internode.on.net etc.

    I have a static IP address service on this prefix, so
    others may be the same, with the host computer, not
    the ADSL modem having the IP address.


  59.167.75.0/24     Internode          76 acks

    ppp75-246.lns1.mel3.internode.on.net etc.

    Jan Whitaker's service is on this prefix.  Presumably
    these are not static, but are like most ADSL services:
    dynamic assignment of IP addresses to various modems
    with the modem presumably doing NAT.  Therefore it must
    be the modem responding to a ping.


  203.214.17.0/24    Iinet              145 acks

    203-214-17-1.dyn.iinet.net.au  etc.

    This prefix is definitely for ordinary dynamically
    assigned ADSL services, with what used to be OzEmail.


Can anyone with an ADSL service tell me their IP address?  I will ping
that /24 subnet.

Cable modems evidently return pings.  As I wrote in:

  http://www.firstpr.com.au/ip/host-density-per-prefix/

the 24.0.0.0/8 prefix (May01 ARIN - Cable Block) acknowledges pings for
17.62 % of its IP addresses.


   - Robin



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