packet dropped issue on fortigate 30E lan ports

[sailesh]

I'm getting weird issues on Fortigate 30E not just on 1 firewall but on multiple 30E firewall. Issue is i got huge packet dropped at all the lan ports while wan port is working fine. 

is there any solution towards this issue?

[AEK]

Which firmware version?

How do you know packets are being dropped at FG LAN ports?

Any related logs?

[sailesh]

* I've been using firmware v6.2.10, v6.2.11, v6.2.15 on multiple device, and same issue persist on all firmware.

* packets are being dropped even if we send ping request form same firewall on different lan interfaces of same firewall.

* there's no any suspicious log or high utilization on any lan ports or memories. However could you pleas explain why i'm getting Interrupt message on executing fnsysctl ifconfig:

Link encap:Ethernet HWaddr 90:6C:AC:53:99:62

UP BROADCAST MULTICAST MTU:1500 Metric:1

RX packets:0 errors:0 dropped:0 overruns:0 frame:0

TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:1000

RX bytes:0 (0 Bytes) TX bytes:0 (0 Bytes)

Interrupt:255

[AEK]

I did a quick search and found that "Interrupt" is the IRQ number associated with the device, something used by CPU, so it is definitely not a kind of error counter.

Since you tried many mature FOS versions and since you have this issue on multiple FG firewalls, my first guess is to check the following:

• Check if there is traffic shaping policy on your firewalls
• Using Cat-5 cables for 1Gb links can lead to such behavior
• Try connect your host directly to your FG and do the test, just to see if the issue is not caused by the switch or other network device
• Temporarily force link speed to 100Mb and do the test. It may reveal some useful result

I also recommend to open a ticket as @Nishtha_Baria suggested.

[Nishtha_Baria]

Dear Customer,

If you are observing packet drops on your FortiGate it would be best to create a ticket with TAC as an engineer can have look and take some real time debugs and packet capture to get to find the root cause of the issue.

-NB