nanog mailing list archives

Re: Application or Software to detect or Block unmanaged swicthes


From: Mel Beckman <mel () beckman org>
Date: Thu, 7 Jun 2018 14:16:25 +0000

When we do NIST-CSF audits, we run an SNMP NMS called Intermapper, which has a Layer-2 collection feature that 
identifies the number and MACs of devices on any given switch port. We export this list and cull out all the known 
managed switch links. Anything remaining that has more than one MAC per port is a potential violation that we can 
readily inspect. It’s not perfect, because an unmanaged switch might only have one device connected, in which case it 
wont be detected. You can also get false positives from hosts running virtualization, if the v-kernel generates 
synthetic MAC addresses. But it’s amazing how many times we find unmanaged switches squirreled away under desks or in 
ceilings.

 -mel 

On Jun 7, 2018, at 4:54 AM, Jason Hellenthal <jhellenthal () dataix net> wrote:

As someone already stated the obvious answers, the slightly more difficult route to be getting a count of allowed 
devices and MAC addresses, then moving forward with something like ansible to poll the count of MAC’s on any given 
port ... of number higher than what’s allowed, suspend the port and send a notification to the appropriate parties.


All in all though sounds like a really brash thing to do to your network team and will generally know and have a very 
good reason for doing so... but not all situations are created equally so good luck.


-- 

The fact that there's a highway to Hell but only a stairway to Heaven says a lot about anticipated traffic volume.

On Jun 7, 2018, at 03:57, segs <michaelolusegunrufai () gmail com> wrote:

Hello All,

Please I have a very interesting scenario that I am on the lookout for a
solution for, We have instances where the network team of my company bypass
controls and processes when adding new switches to the network.

The right parameters that are required to be configured on the switches
inorder for the NAC solution deployed to have full visibility into end
points that connects to such switches are not usually configured.

This poses a problem for the security team as they dont have visibility
into such devices that connect to such switches on the NAC solution, the
network guys usually connect the new switches to the trunk port and they
have access to all VLANs.

Is there a solution that can detect new or unmanaged switches on the
network, and block such devices or if there is a solution that block users
that connect to unmanaged switches on the network even if those users have
domain PCs.

Anticipating your speedy response.

Thank You!

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