By default when you set the ports on hosts max to 1024, after reboot, it goes back to 512 on a stateless host. This is a known issue in the 5.1 release notes.
- maxProxySwitchPorts setting not persistent after stateless host reboot
- The maximum number of ports on a host is reset to 512 after the host is rebooted and a host profile applied. When you set maxProxySwitchPorts on a specific stateless host on a distributed switch, the setting might not persist when the host is rebooted. This applies only to stateless hosts that are part of a distributed switch and have had themaxProxySwitchPorts setting changed.
- Workaround: Manually change the maxProxySwitchPorts settings for the hosts after reboot.
There are 3 ways to make this change, i'll discuss them here.
1) vSphere Windows Client, this way seems to work, but does not. The UI states that the host must be rebooted after the setting is changed. Some experimenting looked like the change did take effect immediately without a reboot and I've confirm in the API guide that a reboot is no longer needed for ESXi 5.1 hosts (http://pubs.vmware.com/vsphere-51/index.jsp?topic=%2Fcom.vmware.wssdk.apiref.doc%2Fvim.dvs.HostMember.ConfigSpec.html), so the "must reboot" label just a UI artifact.
2) Workaround stated above in the release notes using PowerCLI, While changing the maxProxySwitchPorts with PowerCLI does work, it's a pain.
3) Using the NGC (next gen web client). We found the workaround to be setting the "Default max number of ports per host" via the NGC and this does persist between reboots. We tested this on a host that we rebooted and it did come up with 1024 ports.