nanog mailing list archives

Re: Network Segmentation Approaches


From: Christopher Morrow <morrowc.lists () gmail com>
Date: Wed, 6 May 2015 17:25:23 -0400

this is really a form of: "A subnet should contain all things of a
like purpose/use."

that way you don't have to compromise and say: "Well... tcp/443 is OK
for ABC units but deadly for XYZ ones! block to the 6 of 12 XYZ and
permit to all ABC... wait, can you bounce off an ABC and still kill an
XYZ? crap... pwned."

segregation by function/purpose... best bet you can get.


On Wed, May 6, 2015 at 3:59 PM,  <charles () thefnf org> wrote:

Consider setting up a separate zone or zones (via VLAN) for devices
with embedded TCP/IP stacks.  I have worked in several shops using
switched power units from APC, SynAccess, and TrippLite, and find that
the TCP/IP stacks in those units are a bit fragile when confronted
with a lot of traffic, even when the traffic is not addressed to the
embedded devices.


Yes! This.

I used to have my PDUs/term serves/switches all on one VLAN. As growth
occurred, they get broken out to dedicated VLANs. With that, the amount of
false positives from Zenoss went way down (frequently port 80 would report
down, then clear). I still get some alerts, but far less frequently.


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