Unable to communicate with pods on flannel network from pods in the host network

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1

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Cluster information:

Kubernetes version:v1.18.
Cloud being used: (put bare-metal if not on a public cloud) baremetal
Installation method: kubeadm
Host OS: Ubuntu 20.04 LTS
CNI and version:
CRI and version:

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Unable to communicate with pods on flannel network from pods in the host network

 ✘ pasokan@qa-head01  ~  kgpoowide | egrep "busybox-sleep|dnsutils|pasokan-head"
busybox-sleep                         1/1     Running   0          10h     10.244.6.2      sn56        <none>           <none>
dnsutils                              1/1     Running   9          9h      10.244.3.13     sn86        <none>           <none>
pasokan-head                          1/1     Running   0          20d     10.52.96.253    qa-head01   <none>           <none>
 pasokan@qa-head01  ~  kubectl exec --stdin --tty pasokan-head -- /bin/bash
 pasokan@qa-head01  ~  ping -c1 10.244.6.2
PING 10.244.6.2 (10.244.6.2) 56(84) bytes of data.

--- 10.244.6.2 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

 ✘ pasokan@qa-head01  ~  ping -c1 10.244.3.13
PING 10.244.3.13 (10.244.3.13) 56(84) bytes of data.

--- 10.244.3.13 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

 ✘ pasokan@qa-head01  ~ 

within the flannel network it is working

 ✘ pasokan@qa-head01  ~  kubectl exec --stdin --tty busybox-sleep -- sh       
/ # ping -c 1 10.244.3.13
PING 10.244.3.13 (10.244.3.13): 56 data bytes
64 bytes from 10.244.3.13: seq=0 ttl=62 time=0.509 ms

--- 10.244.3.13 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 0.509/0.509/0.509 ms
/ #
2

May need to check that it’s not blocked by a firewall.

One of the things I typically do on a new setup is blow away iptables rules and remove ufw or firewalld; and I just rely on a firewall external to the server.