Sometimes when third party plugins or solutions work with vCenter and ESXi (Like NSX) they will create a custom TCP/IP stack for them to use.

If for whatever reason (say, unclean uninstall) you need to remove the TCP/IP stack you can’t do it from the vCenter GUI, log into each host directly and execute:

esxcli network ip netstack delete -N="stack_name"

E.g. if you are uninstalling NSX and get a stuck vxlan stack:

esxcli network ip netstack remove -N="vxlan"