Description of problem: We had been blocking user to not to be allowed to access the MCS (Machine Config Server) by creating a LoadBalancer service that points to the MCS IP:port but it seems to have regressed recently since last week in QE component readiness. 

Version-Release number of selected component (if applicable): 4.21

How reproducible: Always

Steps to Reproduce:

1. Create a test pod, say hello-pod

2. Create a loadbalancer service that points to TCP port 22623 used by MCS

$ oc get svc
NAME        TYPE           CLUSTER-IP      EXTERNAL-IP                                                              PORT(S)           AGE
hello-pod   LoadBalancer   172.30.23.194   a54147808d31b47e69a1abc5321bf101-855156145.us-east-2.elb.amazonaws.com   22623:32396/TCP   26m

3. Edit hello-pod endpoint to point to master IP

oc patch ep hello-pod -p '{"subsets": [{"addresses": [{"ip": "10.0.31.109"}],"ports": [\{"port": 22623,"protocol": "TCP"}]}]}' --type=merge

Actual results:  Step 3 passed

Expected results: Step 3 should have forbidden with error "endpoint port TCP:22623 is not allowed"

Additional info: Must-gather here

Please fill in the following template while reporting a bug and provide as much relevant information as possible. Doing so will give us the best chance to find a prompt resolution.

Affected Platforms:

Is it an

1. internal CI failure
2. customer issue / SD
3. internal RedHat testing failure

If it is an internal RedHat testing failure:

• Please share a kubeconfig or creds to a live cluster for the assignee to debug/troubleshoot along with reproducer steps (specially if it's a telco use case like ICNI, secondary bridges or BM+kubevirt).

If it is a CI failure:

• Did it happen in different CI lanes? If so please provide links to multiple failures with the same error instance
• Did it happen in both sdn and ovn jobs? If so please provide links to multiple failures with the same error instance
• Did it happen in other platforms (e.g. aws, azure, gcp, baremetal etc) ? If so please provide links to multiple failures with the same error instance
• When did the failure start happening? Please provide the UTC timestamp of the networking outage window from a sample failure run
• If it's a connectivity issue,
• What is the srcNode, srcIP and srcNamespace and srcPodName?
• What is the dstNode, dstIP and dstNamespace and dstPodName?
• What is the traffic path? (examples: pod2pod? pod2external?, pod2svc? pod2Node? etc)

If it is a customer / SD issue:

• Provide enough information in the bug description that Engineering doesn't need to read the entire case history.
• Don't presume that Engineering has access to Salesforce.
• Do presume that Engineering will access attachments through supportshell.
• Describe what each relevant attachment is intended to demonstrate (failed pods, log errors, OVS issues, etc).
• Referring to the attached must-gather, sosreport or other attachment, please provide the following details:
  • If the issue is in a customer namespace then provide a namespace inspect.
  • If it is a connectivity issue:
    • What is the srcNode, srcNamespace, srcPodName and srcPodIP?
    • What is the dstNode, dstNamespace, dstPodName and dstPodIP?
    • What is the traffic path? (examples: pod2pod? pod2external?, pod2svc? pod2Node? etc)
    • Please provide the UTC timestamp networking outage window from must-gather
    • Please provide tcpdump pcaps taken during the outage filtered based on the above provided src/dst IPs
  • If it is not a connectivity issue:
    • Describe the steps taken so far to analyze the logs from networking components (cluster-network-operator, OVNK, SDN, openvswitch, ovs-configure etc) and the actual component where the issue was seen based on the attached must-gather. Please attach snippets of relevant logs around the window when problem has happened if any.

• When showing the results from commands, include the entire command in the output.  
• For OCPBUGS in which the issue has been identified, label with "sbr-triaged"
• For OCPBUGS in which the issue has not been identified and needs Engineering help for root cause, label with "sbr-untriaged"
• Do not set the priority, that is owned by Engineering and will be set when the bug is evaluated
• Note: bugs that do not meet these minimum standards will be closed with label "SDN-Jira-template"
• For guidance on using this template please see
  OCPBUGS Template Training for Networking  components