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itc
New Contributor II

GRE Tunel not working after 7.4.1 > 7.4.3

Hi

My GRE tunel connection is not working after upgrade FortiOS from 7.4.1 > 7.4.3.

Forti shows, that connection is UP but I have no access  to network. 

Checked policies, diagnosed connection and everything looks fine.

Any idea what to check next? How to monitor?

 

Best regards,

Rafal

25 REPLIES 25
rtanagras
Staff
Staff

Hi @Rafal - You can try disabling "np-acceleration" and "auto-asic-offloading" to troubleshoot the issue. Additionally, examining the sniffer output and using the debug flow command can provide more insights.

Best,
Ricky
hbac
Staff
Staff

Hi @itc,

 

Are you using NAT? Are there any IP pools/VIPs related to local/remote subnets of the GRE tunnel? There was a behavior change on the new version which might cause the issue. Please refer to https://community.fortinet.com/t5/FortiGate/Technical-Tip-IP-pool-behavior-Change-in-default-ippool/...

 

Regards, 

infor1
New Contributor

I have the same problem. Have you solved the problem?

AEK
Honored Contributor II

Try follow @rtanagras and @hbac suggestions.

AEK
AEK
infor1
New Contributor

I used it, but it helped. I had to go back to the old firmware. The old one works ok.

in log knowledge this :
anti-spoof check failed,drop

michaeljhones72
New Contributor

GRE tunnel after the upgrade. Double-checking the configuration and policies is a good start. You might want to review logs and monitor traffic flow to identify any anomalies Contact.

Deltaman
New Contributor II

Hi,

 

I have the same issue and have made a case.

GRE Tunnel not working after 7.4.1 > 7.4.2 or 7.4.3. Roll back solves the issue

 

With diagnose sniffer I can see that traffic is only inbound and not outbound. Interfaces show status up, but traffic is not encapsulated when needs to go outbound.

 

Also I have seen that the route for data that should travel through the GRE tunnel is not installed when running firmware 7.4.2 or 7.4.3.

 

Regards,

Hugo

 

AEK
Honored Contributor II

Hi Hugo

That's interesting info.

Did you try manually install the missing route to see if it fixes the issue?

AEK
AEK
Deltaman
New Contributor II

Yes I did, but the routes does then also not get installed, then you would think that the interface is not up what causes the route to be not installed.

 

But GUI displayes as interfaces are all up.

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