RHEL8.6GA: issues with asymmetric routing

Solution Verified - Updated -

Issue

We are using a router based on CentOS Stream 8 and nft with iptables-services. In some cases we have asymmetric traffic passing through this router. After upgrading to 4.18.0-365 we have noticed weird port mapping during FORWARD. Rolling back to 4.18.0-348.7.1.el8_5.x86_64 does not show this behavior.

We can reproduce the behavior.

We did not see this behavior prior to kernel 4.18.0-365 and we are using such configuration already for years. We are not sure if it's a bug or a feature. Has something changed and should we untrack such traffic or is it a bug?

Environment

  • Red Hat Enterprise Linux (RHEL) 8.6
  • CentOS Stream 8
  • kernel 4.18.0-365.el8 and later
  • nft
  • networking

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