# DHCP Snooping Parameters and Commands
**URL:** https://community.cambiumnetworks.com/t/dhcp-snooping-parameters-and-commands/59175
**Category:** cnMatrix
**Tags:** knowledge-base
**Created:** [December 4, 2018, 12:03pm UTC](https://community.cambiumnetworks.com/t/dhcp-snooping-parameters-and-commands/59175 "2018-12-04T12:03:47Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@sdespan](https://community.cambiumnetworks.com/u/sdespan)
#### Post date: [December 4, 2018, 12:03pm UTC](https://community.cambiumnetworks.com/t/dhcp-snooping-parameters-and-commands/59175/1 "2018-12-04T12:03:47Z")
- [Parameters and Commands DHCP Snooping .pdf](https://d1okf4ta8xniw3.cloudfront.net/original/2X/d/d476ce2b794029f9925ce693a84db1c72225abeb.pdf) (352 KB)
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### Author:  [@BradenMcG\_DC](https://community.cambiumnetworks.com/u/BradenMcG_DC)
#### Post date: [October 2, 2026, 7:45pm UTC](https://community.cambiumnetworks.com/t/dhcp-snooping-parameters-and-commands/59175/2 "2026-10-02T19:45:18Z")
This seems like as good a place as any to drop this pearl of wisdom…
cnMatrix switches, when DHCP snooping is enabled, seem to do something with DHCP requests or replies that cause problems when you have multiple tiers of switching with snooping enabled on all of them.
With most other vendors’ switches, you only set a port to “trusted” if it’s actually facing or connected to the DHCP server; with cnMatrix, you also need to “trust” any port that is facing a _downstream_ switch that has snooping enabled.
I would _expect_ this sort of behavior if the downstream switch is configured to inject additional DHCP options (like port-id or something)… but there does not seem to be a way to toggle that behavior that I could see (or at least not in cnMaestro).
**TL;DR version** : with cnMatrix switches, set ports on **both sides** of an inter-switch link (the child’s upstream ports, and the parent’s _downstream_ ports) to be “Trusted” if you are running snooping on both switches. Client-facing ports should remain “untrusted” throughout.