IP / Network Issue

Palo Alto Networks firewall: MAC table full

Q: Where can I find the Palo Alto Networks official documentation?

https://knowledgebase.paloaltonetworks.com — search the product family + feature name.

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

⚡ At a glance

Vendor	Palo Alto Networks
Operating system	PAN-OS
Category	IP / Network Issue
Skill level	Intermediate to advanced
DIY-able?	Yes with CLI access; some scenarios need Palo Alto TAC + RMA.

What this guide covers

Fix MAC table full on a Palo Alto Networks firewall.

Step-by-step

Check current MAC table utilisation.
Identify the offending VLAN or port.
Enable storm-control on access ports.
Enable port-security with a hard MAC limit.
Long-term, refresh to a switch with a larger MAC table.

CLI / commands

show interface all
show interface ethernet1/1
show system state filter sys.s1.p*

When the issue persists

Open a Palo Alto TAC case with the tech-support bundle.
Provide the timeline + recent changes.

Frequently asked questions

Will this work on my specific PAN-OS version?

The procedure reflects current PAN-OS behaviour. Older releases may need minor syntax adjustments, use the CLI help (? or tab-completion) to verify.

Should I open a Palo Alto TAC case immediately?

Open one if you suspect hardware failure or the symptom persists after a maintenance-window reload. Make sure your support entitlement is active first.

Where can I find the Palo Alto Networks official documentation?

https://knowledgebase.paloaltonetworks.com: search the product family + feature name.

Is this procedure safe in production?

Test in a lab or maintenance window first. Capture pre-change state so you can roll back.

All Palo Alto Networks fix guides → /paloalto/
All vendor guides → /vendors/

Related guides worth a look while you sort this one out:

References

Palo Alto Networks support portal: https://support.paloaltonetworks.com
Palo Alto Networks knowledge base: https://knowledgebase.paloaltonetworks.com
Palo Alto Networks security advisories: https://security.paloaltonetworks.com
Open a case: https://support.paloaltonetworks.com/Support/Index

Reference material, not professional advice. Validate against your specific PAN-OS version and test in a non-production environment before applying.

What changed recently?

Fault diagnosis on a Palo device goes faster when you map the symptom to a recent change:

Did firmware update in the last 7 days?
Did the network (router, ISP, VPN) change?
Was the device moved physically?
Did paired devices (phone, hub, app) update?
Were any accessories swapped in or out?

The answer narrows the root cause to a manageable subset.

Before you start

A few things to confirm so the Palo device fix goes cleanly:

Latest firmware downloaded if you're going to update.
Warranty + support contract status checked, opening sealed parts may void it.
Backup of current configuration (where applicable) taken.
Spare parts on hand if you anticipate replacement.
Adequate workspace, lighting, and time. rushing causes regressions.

Verification checklist

After applying the fix on your Palo device, confirm:

The original symptom is no longer reproducible.
Related features (status LEDs, app sync, paired accessories) still work.
The device responds to a soft reboot without the fault returning.
Any error codes that were on display have cleared.
Documentation (your service log, the brand companion app) reflects the change.

When to call Palo support instead

Escalate if:

The same symptom returns within 24 hours of a clean fix.
You see physical damage (burn marks, swollen battery, cracked PCB).
The device is in warranty and a hardware replacement is the cheaper outcome.
Repair requires specialised tools you don't own (alignment jigs, calibration software).
Following the official path keeps the warranty intact, which matters more than the time spent.