RFC 1918 restricts these address ranges to internal, privately-assigned IP
subnets:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
So 127.* and 198.* may or may not be internal, but the 10.* addresses
definitely are.
LMcQ
Laurie McQuillan, CISSP
Program Manager, Network Designs - FAA AVR Information Security
Office: 202-493-4415 Cell: 703-980-2428 eFax: 703-832-0785
eMail: [EMAIL PROTECTED] or [EMAIL PROTECTED]
"You will only be remembered for two things:
the problems you solve, or the ones you create."
-----Original Message-----
From: scott [gts] [mailto:[EMAIL PROTECTED]]
Sent: Friday, October 26, 2001 3:26 PM
To: security-basics
Subject: RE: help - can someone explain this to me?
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im pretty sure that 10.*, 127.* and 198.* are not routable
on the internet (which is why so many LANs use them), so it
looks like whatever happened to your machine is coming
from inside the LAN where your machine is hosted.
perhaps a machine that the ISP hosts is infected with something
and throwing out packets to everything on the LAN...?
(maybe it's another damn IIS worm, since it appears
that your ISP hosts mostly NT/IIS machines)
but dont take my word, that's just a speculation, i'm
not a networking specialist or anything.
> -----Original Message-----
> From: Steven M Bloomfield [mailto:[EMAIL PROTECTED]]
> Subject: help - can someone explain this to me?
>
> Hi,
> I'm webmaster of a large-ish website and yesterday the server went
down.
> It is a Redhat 6.1 Linux server. All my ISP would do was press the
'reset'
> button - very kind of them (they are NT specialists).
> Inspecting my log files I found thousands of denied packets, all seem to
be
> within a period of 6 hours.
> My question is, could such an attack disable my machine and crash it? Can
> anyone identify what sort of attack it was?
>
> Here's a summary below:
>
> Denied packets from modem-392.awesome.dialup.pol.co.uk (62.25.129.136).
> Port https (tcp,eth0,input): 5 packet(s).
> Total of 5 packet(s).
>
> Denied packets from 10.10.71.237.
> Port netbios-dgm (udp,eth1,input): 69 packet(s).
> Port netbios-ns (udp,eth1,input): 333 packet(s).
> Total of 402 packet(s).
>
> Denied packets from 10.10.0.4.
> Port netbios-dgm (udp,eth1,input): 496 packet(s).
> Port netbios-ns (udp,eth1,input): 2925 packet(s).
> Total of 3421 packet(s).
>
> Denied packets from userSg017.videon.wave.ca (204.112.48.37).
> Port 500 (udp,eth0,input): 6 packet(s).
> Total of 6 packet(s).
>
> Denied packets from 207.190.199.102.
> Port https (tcp,eth0,input): 11 packet(s).
> Total of 11 packet(s).
>
> Denied packets from 10.10.32.21.
> Port netbios-dgm (udp,eth1,input): 338 packet(s).
> Port netbios-ns (udp,eth1,input): 1742 packet(s).
> Total of 2080 packet(s).
>
> Denied packets from 172.17.0.18.
> Port 1434 (udp,eth1,input): 2 packet(s).
> Total of 2 packet(s).
>
> Denied packets from 10.10.1.37.
> Port netbios-dgm (udp,eth1,input): 496 packet(s).
> Port netbios-ns (udp,eth1,input): 2925 packet(s).
> Total of 3421 packet(s).
>
> Denied packets from 10.10.32.27.
> Port netbios-dgm (udp,eth1,input): 59 packet(s).
> Port netbios-ns (udp,eth1,input): 324 packet(s).
> Total of 383 packet(s).
>
> Denied packets from 10.10.32.28.
> Port netbios-dgm (udp,eth1,input): 107 packet(s).
> Port netbios-ns (udp,eth1,input): 513 packet(s).
> Total of 620 packet(s).
>
> Denied packets from 10.10.0.1.
> Port 0 (tcp,eth1,input): 3 packet(s).
> Total of 3 packet(s).
>
> Denied packets from 10.10.0.3.
> Port bootpc (udp,eth1,input): 19 packet(s).
> Port netbios-dgm (udp,eth1,input): 475 packet(s).
> Port netbios-ns (udp,eth1,input): 2259 packet(s).
> Total of 2753 packet(s).
>
> Thanks,
Steve
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