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chethan
Explorer II
May 11, 2022
Solved

Inter-VLAN routing issues - FortiGate

  • May 11, 2022
  • 12 replies
  • 36950 views

Hello everyone,

 

Before implementing the following configuration in production I'm testing it out in GNS3 and I'm facing issues with Inter-VLAN routing. I have configured FortiGate to act as router-on-a-stick.

 

  1. I have created VLAN 100 and VLAN 200 on the switch and allowed it over the trunk interface that is connected to the FortiGate. Configured the ports connecting the end devices as access ports.
  2. Created same VLANs on the FortiGate and attached it to the interfaces that is connected to the switch.
  3. Created the required Firewall polices, VLAN 100 -> VLAN 200 and VLAN 200 -> VLAN 100.
  4. From device in VLAN 100, I'm able to ping the VLAN 100 SVI IP address and the SVI IP address on VLAN 200. But unable to reach the other device in VLAN 200 and vice-versa.
  5. Packet sniffer on FortiGate shows that It is receiving the packet on VLAN 100 interface but it is not sending it out of VLAN 200 interface. 

Please, find the attached images for the reference. I believe I'm not missing anything here. Any suggestions would be helpful.

 

 

Network Diagram:

 

chethan_1-1652270777734.png

 

Firewall Polices:

 

chethan_2-1652270777739.png

 

VLAN Interface details:

 

chethan_3-1652270777742.png

 

Sniffer Output:

 

chethan_4-1652270777744.png

 

Thank you

 

 

 

IMPORTANT UPDATE: 

 

Hey everyone,

 

This is important I guess,

 

I just replaced the new FortiGate running FortiOS 7.2 with ForiOS 6.4.9. And, Inter-VLAN routing is happening now without any problem.

 

I have same configuration in place like the one that I had earlier.

 

Is this a bug or anything in 7.2 release? Can the Fortinet staff confirm this please?

 

Please find my updated screenshots:

 

chethan_0-1652357915030.png

 

PC1 to PC2:

chethan_1-1652357937273.png

 

PC2 to PC1:

chethan_2-1652357956362.png

 

Thank you

 

 

 

 

Best answer by jintrah_FTNT

Hi Chethan,

 

I tested this on a 7.2 device and it is found to work, so issue should be local to your environment only.

 

jintrah_FTNT_0-1652428999364.pngjintrah_FTNT_1-1652429192067.png

 

jintrah_FTNT_2-1652429279470.png

 

best regards,

Jin

 

12 replies

binover
New Member
May 30, 2022

Hi, did you have any update? I reached this board looking for a similar issue. What we noteced is only happened with ICMP, TCP and UDP is routed fine but is impossible to reach the hosts with ping. We also hace FortiOS 7.x on a stack with Fortiswitches. Any idea?

chethan
chethanAuthor
Explorer II
May 31, 2022

Hello,

 

It was a virtual environment and I believed the issue is to local to my system. 

It is working fine with a physical FortiGate.

 

What firmware are you currently running?

 

Thank you.

 

Pantsu
New Member
July 3, 2025

Hello, I’m experiencing the same issue on EVE-NG. My FortiGate version is: FortiGate-VM64-KVM v7.2.11, build 1740, 250210.
Was this problem only solved by downgrading?