Problem with FGSP and FGCP

[maxiboom]

Hello everyone,

FortiOS: 7.2.4

Fortigate: 200E

We have two FGCP clusters and FGSP between them. FGCP clusters are georaphically spaced and RTT between them around 40-50 ms. Session sync is configured over L3 link between FGCP clusters.

We have configured pickup sessions(also expectation and connectionless).

1st FGCP cluster:

config system ha
  set group-name "cluster 01"
  set mode a-p
  set session-pickup enable
  set session-pickup-connectionless enable
  set session-pickup-expectation enable
  set ha-mgmt-status enable
  set override disable

config system standalone-cluster
  set standalone-group-id 1
  set group-member-id 1
  config cluster-peer
    edit 1
      set peerip x.x.x.x

diagnose sys ha standalone-peers
  Group=1, ID=1
  Detected-peers=1
  Kernel standalone-peers: num=1.
    peer0: vfid=0, peerip:port = y.y.y.y:708, standalone_id=2
    session-type: send=249986, recv=403283
    packet-type: send=0, recv=0

2nd FGCP cluster:

config system ha
  set group-name "cluster 02"
  set mode a-p
  set session-pickup enable
  set session-pickup-connectionless enable
  set session-pickup-expectation enable
  set ha-mgmt-status enable
  set override disable

config system standalone-cluster
  set standalone-group-id 1
  set group-member-id 2
  config cluster-peer
    edit 1
     set peerip y.y.y.y

diagnose sys ha standalone-peers
  Group=1, ID=2
  Detected-peers=1
  Kernel standalone-peers: num=1.
  peer0: vfid=0, peerip:port = x.x.x.x:708, standalone_id=1
  session-type: send=202291, recv=4528433
  packet-type: send=0, recv=0

Sessions are synchronized without problem.

So, problem is following:

When traffic symmetrical we have no problem. Symmetrical traffic mean that traffic came out from and came back to the same FGCP cluster (for example 1st FGSP cluster).

But when traffic asymmetrical we have problem: using icmp as an example we have lost first or two packets. Using TCP we have long connection, for example, to smtp services. Using UDP, for example, DNS server sometimes has timeout error. Asymmetrical traffic mean that traffic came out from one FGCP cluster and came back to another FGCP cluster (for example came out from 1st FGSP cluster and came back to 2nd FGSP cluster). So, we have this problem with both TCP and UDP.

For now we have following investigation results:

1) This problem is not related to traffic inspection and observed on both type of rules: with traffic inspection and without traffic inspection.

2) We don't observe this problem when traffic just go through FGCP clusters without NAT.

3) We don't observe this problem when traffic symmetrical.

4) Session synchronization occurs instantly with first packet on one of the FGCP cluster.

So, I suppose problem with NAT. But actually how can I debug this? Maybe some tuning options exist? Has someone encountered such a problem?

[AEK]

Hi

I've faced something similar for UTM sessions only, and could finally fix it by tuning the below params:

• FGSP configuration -> unset session-sync-dev
• HA configuration -> set sync-packet-balance enable
• UTM policy -> set auto-asic-offload disable

Hope this helps