Palo Alto Networks firewall: TCAM exhausted (routes / ACL entries)

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

What this guide covers

Fix TCAM exhausted (routes / ACL entries) on a Palo Alto Networks firewall.

Step-by-step

1. Check current TCAM usage.
2. If routes exceed the limit, switch to a routing-prefer SDM template if available.
3. Simplify or split ACLs across multiple devices.
4. Refresh to a model with a larger TCAM.

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.

Related guides

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

Related fixes

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

• Best Palo Alto Networks firewall for branch office
• Best Palo Alto Networks firewall for enterprise data centre
• Best Palo Alto Networks firewall for retail store
• Best Palo Alto Networks firewall for SD-WAN deployment
• Best Palo Alto Networks firewall for small office
• Best Palo Alto Networks firewall for SMB under USD 5000

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.

How to confirm it's actually fixed

On a Palo device, the test is rarely "reboot and see". Use this list:

• Active reproduction: trigger the original failure path on purpose.
• Indirect reproduction: do an activity that would expose the same subsystem.
• Status indicator review: every LED / display / app status should be green.
• 24-hour soak: leave the device under normal load overnight; check the next morning.
• Telemetry check: review the device or app's diagnostic log for new error entries.

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.

More frequently asked questions

Why is this happening on a brand-new unit?

Out-of-box defects do occur. If you've owned the device under 30 days and the symptom persists after a factory reset, escalate to the seller for replacement under DOA terms before opening a manufacturer support case.

What if my model isn't exactly the same revision?

Cross-check the model code on the rating plate against the manufacturer support page. Major firmware generations sometimes shift the menu path; the option is usually under a similarly-named section.

Will the procedure work on the international variant?

Some features and firmware paths are region-locked. Check the model spec sheet to confirm your variant supports the menu option referenced. If you're outside the US/EU, look for the regional support portal.

Can I roll this back if something breaks?

Yes for software-level changes (firmware rollback, config rollback). Hardware changes are usually one-way. Always back up settings before starting.

Will this void my warranty?

Applying official firmware updates and following the user manual will not affect warranty. Opening sealed components, jumping safety circuits, or using third-party parts can void warranty in most jurisdictions.