🔐 When a Firewall Goes to SUSPEND – It’s Not Always a Firewall Issue

Today I handled an incident where a Palo Alto Firewall was reported in Suspend mode.
At first glance, it looked like a firewall failure — but the real story was deeper.

🔍 What actually happened:

Firewall entered Suspend mode due to Non-functional loop detected

Initial checks showed BGP was down (Idle state)

A manual attempt to bring the firewall up moved it to Tentative (Path Down) state

Further investigation revealed the BGP peer IP had been changed

Because of the incorrect peer IP:

BGP session never established

Routes were withdrawn

Firewall fell back to unsafe routing

Palo Alto correctly protected the network by suspending traffic



🛠 Resolution:

Corrected the BGP peer IP

BGP session moved to Established

Routes were re-learned

HA path monitoring became healthy

Firewall automatically transitioned to Functional state


🧠 Key Takeaway:

> Suspend and Tentative modes are not failures — they are safety mechanisms.
Palo Alto firewalls prefer to stop forwarding traffic rather than risk routing loops or instability.



✅ Lessons Learned:

Firewall issues often originate from routing or design changes

Never force a firewall to Functional while BGP is unstable

Always validate BGP peer configuration after changes

Strong designs fail safely — and this is a perfect example