PBF conflict with "ip strict option" in zoon protection

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PBF conflict with "ip strict option" in zoon protection

L2 Linker

Hi All

i have a scenario where the traffic works fine if it's forwarded by the routing table (and nat is applied)

when i used pbf, it didn't work, checking global counters i found oacket are dropped and the reason is "strict ip" option in the zone protection profile.

I run debug flow basic and got this message : 

"source ip address in packet does not belong to interface address, packet dropped" 

unchecking this option fixed the issue.


I did little research on this option and found it's releated to malformed packets not spoofing 


we have spoofing check enabled but it's not affecting the operation (tried disabling it but everything is same)


So i see strict is making the spoof check but on the return traffic . Is that normal ?! 


PAN OS 9.0.9-h1




Accepted Solutions

L2 Linker

The s2c traffic is dropping because of Strict IP is failing due to the source IP address is not routable over the exact ingress interface. The firewall decides if the address is routable by checking the routing table to see if a route exists for the server to use that interface.


Disabling Strict IP Address Check would allow the s2c traffic through the firewall, but it also introduces a security risk for that zone as well.


A better solution would be to add a route for the server address to use that interface. This would allow Strick IP Address Check can stay enabled and the routable check to succeed.

View solution in original post


Cyber Elite
Cyber Elite



Please see below document.

Also Recommended version for 9.1 is 9.1.4.






I couldn't see any document below , could you please share it. 


For the PAN OS , customer is still running 9.0 , is this topic related to the upgrade to 9.1 ?



L4 Transporter



from the little infos you wrote on your problem i will say, you have a problem with the returning traffic.

just use "enforce symmetric return".



Hi @Abdul-Fattah Thanks for your reply . We tried already, result is same . We had to uncheck "strict ip" .


Why "strict ip" is affected by the routing,! isn't it for malfored packets/reserved IPs ,.. ?



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