For example preventing it from sending arp, stp, etc and to reveal as little as possible about the rest of the network.

Example use case would be connecting to a peering exchange.

5 Answers 5


You can check the Amsterdam Internet Exchange's Config Guide for hints on how to silence switches from a variety of vendors.

In my experience there are vendors whose software is so bad that their equipment is never silent, for example they ARP out every interface when they boot, or send out some upon a link up event on a port. Juniper, Cisco, Brocade can be muffled with varying degrees of persuasion, Extreme loops everything during EAPS transitions.

Some things to disable/consider:

  • Discovery protocols (LLDP, CDP, FDP, 'dynamic-vlan-discovery')
  • VTP, DTP
  • STP (disable for the VLAN a port is in)
  • Ethernet keepalives or loop frames (useless on full-duplex media)
  • Weird stuff like DECnet MOP (topic of another question a few days ago)
  • Have a separate management VLAN for the switch's own IP address
  • You'll want to disable PIM snooping on a Cisco as this breaks IPv6.

This is where switches such as the Metro-E series from Cisco come in, by default all the downstream ports run in UNI mode which means that they dont send out CDP, STP or any frames at all from other UNI ports.

Another thing you could look at is private VLAN's and then disabling things like CDP.


You can search cisco-nsp@ for different propositions as to what to enable/disable on the ports. For example start here:


Depending on your particular Cisco switch - Catalyst or Nexus, you may also search cisco.com for specific design practices. For example, for Catalyst 6500:



also worth ensuring you nail down .1q/tagging negotiation http://www.curtis-lamasters.com/cisco-switching-switchport-nonegotiate/


cisco have the option 'switchport protected' that can provide basic L2 protection between ports. No traffic can be exchanged between protected ports. Yet, they can send and receive traffic to/from unprotected ports.

  • That does little to make the port silent. It only limits who will hear it.
    – Ricky
    May 21, 2013 at 18:21

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