nanog mailing list archives

Re: Does Anyone Care?


From: Bjorn Carlsson <bc () ebone net>
Date: Fri, 11 Feb 2000 08:55:54 +0100


Hi,

Not sure I follow. schnell.ebone.net is actually an interface of Sprint
icm-bb1-pen which connects to a FDDI ring in Pennsauken built for multicast.
The name/address (schnell.ebone.net) is there for historial reasons and
should be changed to something-else.icp.net.

As for directed broadcast it is long since turned off on all EBONE
routers.

--BC

Ok, here's some more stuff on the directed broadcast out of the 
Sprint NAP in Pennsauken, NJ.

1) Directed broadcasts weren't disabled at the Spokane, WA router and
   whoever was doing this attack was aware of that fact. I managed to
   disable it and write that change to memory.

   If you decided to check that router anytime soon (spn-brdr-01) check
   the counters on the Fddi1/1/0 interface that links to the Pennsauken
   NAP. You'll see that 99% of the traffic coming through are directed
   broadcasts.

2) If you decided to restore the configuration on that router, I suggest
   you go back in and disable directed broadcasts on the Ebone interface
   (Fddi1/1/0) because it wasn't disabled when I initally logged in and
   the directed broadcast still appears to be active (4:28pm EST,
   February 10, 1999).

   traceroute to schnell.ebone.net (192.36.137.1): 1-30 hops, 38 byte packets
    1  vdi-dialup.vdi.net (209.201.95.2) [AS3951 - NETBLK-ICON-NET5]  109 ms 130 ms  110 ms
    2  router.vdi.net (209.3.31.1) [AS3951 - NETBLK-ICON-NET4]  110 ms 130 ms  120 ms
    3  Hssi3-0-0.border2.teb1.IConNet.NET (209.3.187.253) [AS3951 - NETBLK-ICON-NET4]  120 ms  139 ms  120 ms
    4  POS10-0-0.core1.teb1.IConNet.NET (204.245.71.201) [AS3951 - ICon CMT Corp.]  120 ms  149 ms  120 ms
    5  205.171.4.217 (205.171.4.217) [AS3909 - Colorado Supernet, Inc.] 119 ms  149 ms  120 ms
    6  205.171.4.134 (205.171.4.134) [AS3909 - Colorado Supernet, Inc.] 140 ms  158 ms  120 ms
    7  schnell.ebone.net (192.36.137.1)  230 ms (ttl=244!)  259 ms (ttl=244!)  *

   Notice the latency jump at the last hop, five other traceroutes showed
   similar data.

3) Check the NYC core router (nyc-core-01) and look at the Teleglobe and
   Spokane interfaces, earlier that day, there was approximately 75mbps
   coming in on the Teleglobe interface (POS0/0) and the same amount being
   output to the Spokane-bound interface.

4) I shutdown the Sprint interface (Fddi2/1/0) on the Spokane border
   router for about 30 seconds, and there was approximately a 5mbps  
   decrease in the directed broadcasts coming from Ebone at the Pennsauken
   NAP.

5) I then shutdown the Ebone interface (Fddi1/1/0) on the Spokane border
   router for about 30 seconds, and there was approximately a 10mbps  
   decrease in the outgoing traffic of the Sprint interface (Fddi2/1/0).

6) The interface statistics on the Sprint interface (Fddi2/1/0) showed
   there were some broadcasts being sent, but not as numerous as the Ebone
   the interface, I would advise you check the other side of that
   interface for abnormal activity.

7) If you normally keep track of all your customers' bandwidth
   utilization, look for excessive peaks in the incoming and outgoing
   paths along with for anything that has jumped excessively in the past
   three days.

Omachonu Ogali
Intranova Networking Group




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